| From pgsql-general-owner@postgresql.org Tue Oct 1 14:28:01 2002 |
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| Date: Tue, 1 Oct 2002 11:27:56 -0700 (PDT) |
| From: Stephan Szabo <sszabo@megazone23.bigpanda.com> |
| To: Adam Siegel <adam@sycamorehq.com> |
| Cc: <pgsql-general@postgresql.org>, |
| <pgsql-performance@postgresql.org> |
| Subject: Re: [pgsql-performance] Deletes from tables with foreign keys taking |
| In-Reply-To: <00ca01c26978$490ee4a0$1537140a@orbital.com> |
| Message-ID: <20021001112632.F96255-100000@megazone23.bigpanda.com> |
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|
|
| On Tue, 1 Oct 2002, Adam Siegel wrote: |
|
|
| > I have a table that has about 200 rows in it. I have 2 other tables |
| > that have about 300,000 rows each that reference the first table |
| > through a foriegn key. I run a process that rebuilds these tables. |
| > First I delete the rows in the large tables (takes about 30 seconds), |
| > then I delete the the rows in the first table (takes about 5 minutes |
| > !!!). Each of these are done in separate transactions. |
| > |
| > If I do a vacuum analyze on each of the large tables just after the |
| > delete then deleting the rows from the first table takes just a second |
| > or two. My guess is that postgres is still check the foriegn keys |
| > from the first table to the others even though the records are deleted |
| > in the larger tables. The vacuum cleans up the deleted records, so it |
| > goes faster. Am I wrong. Any ideas? |
|
|
| That seems reasonable. It's still going to be doing some action on those |
| tables and it's going to have to scan the tables in some case. It's wierd |
| that it's taking that long to do it in any case however, what does the |
| schema for the tables look like? |
|
|
|
|
|
|
|
|
| From pgsql-general-owner@postgresql.org Tue Oct 1 14:23:53 2002 |
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| Tue, 1 Oct 2002 14:23:50 -0400 |
| Message-ID: <00ca01c26978$490ee4a0$1537140a@orbital.com> |
| From: "Adam Siegel" <adam@sycamorehq.com> |
| To: <pgsql-general@postgresql.org>, |
| <pgsql-performance@postgresql.org> |
| Subject: Deletes from tables with foreign keys taking too long |
| Date: Tue, 1 Oct 2002 14:28:04 -0400 |
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|
| This is a multi-part message in MIME format. |
|
|
| |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| Content-Transfer-Encoding: quoted-printable |
|
|
| I have a table that has about 200 rows in it. I have 2 other tables that h= |
| ave about 300,000 rows each that reference the first table through a forieg= |
| n key. I run a process that rebuilds these tables. First I delete the row= |
| s in the large tables (takes about 30 seconds), then I delete the the rows = |
| in the first table (takes about 5 minutes !!!). Each of these are done in = |
| separate transactions. |
|
|
| If I do a vacuum analyze on each of the large tables just after the delete = |
| then deleting the rows from the first table takes just a second or two. My= |
| guess is that postgres is still check the foriegn keys from the first tabl= |
| e to the others even though the records are deleted in the larger tables. = |
| The vacuum cleans up the deleted records, so it goes faster. Am I wrong. = |
| Any ideas? |
|
|
| Regards, |
| Adam |
|
|
|
|
|
|
| |
| Content-Type: text/html; |
| charset="iso-8859-1" |
| Content-Transfer-Encoding: quoted-printable |
|
|
| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
| <HTML><HEAD> |
| <META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-8859-1"> |
| <META content=3D"MSHTML 6.00.2719.2200" name=3DGENERATOR> |
| <STYLE></STYLE> |
| </HEAD> |
| <BODY bgColor=3D |
| <DIV><FONT face=3DArial size=3D2>I have a table that has about 200 rows in = |
| it. =20 |
| I have 2 other tables that have about 300,000 rows each that reference the = |
| first=20 |
| table through a foriegn key. I run a process that rebuilds these=20 |
| tables. First I delete the rows in the large tables (takes about 30= |
| =20 |
| seconds), then I delete the the rows in the first table (takes about 5 minu= |
| tes=20 |
| !!!). Each of these are done in separate transactions.</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV> |
| <DIV><FONT face=3DArial size=3D2>If I do a vacuum analyze on each of the la= |
| rge=20 |
| tables just after the delete then deleting the rows from the first table ta= |
| kes=20 |
| just a second or two. My guess is that postgres is still check the fo= |
| riegn=20 |
| keys from the first table to the others even though the records are deleted= |
| in=20 |
| the larger tables. The vacuum cleans up the deleted records, so it go= |
| es=20 |
| faster. Am I wrong. Any ideas?</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV> |
| <DIV><FONT face=3DArial size=3D2>Regards,</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2>Adam</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV></BODY></HTML> |
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| |
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|
| From pgsql-general-owner@postgresql.org Fri Oct 4 09:38:41 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id E7A74476944; Tue, 1 Oct 2002 17:45:12 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
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| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: "Adam Siegel" <adam@sycamorehq.com>, |
| <pgsql-general@postgresql.org>, <pgsql-performance@postgresql.org> |
| Subject: Re: [pgsql-performance] Deletes from tables with foreign keys taking |
| too long |
| Date: Tue, 1 Oct 2002 14:44:05 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <00ca01c26978$490ee4a0$1537140a@orbital.com> |
| In-Reply-To: <00ca01c26978$490ee4a0$1537140a@orbital.com> |
| MIME-Version: 1.0 |
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|
|
| Adam, |
|
|
| > I have a table that has about 200 rows in it. I have 2 other tables that |
| > have about 300,000 rows each that reference the first table through a |
| > foriegn key. I run a process that rebuilds these tables. First I delete |
| > the rows in the large tables (takes about 30 seconds), then I delete the |
| > the rows in the first table (takes about 5 minutes !!!). Each of these a= |
| re |
| > done in separate transactions. |
|
|
| Not that this answers your performance questions, but you will be able to d= |
| o=20 |
| this faster if you use TRUNCATE instead of DELETE. |
|
|
| |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 1 17:52:38 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 41A164762C6 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 1 Oct 2002 17:52:37 -0400 (EDT) |
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| Tue, 01 Oct 2002 14:53:08 -0700 |
| Content-Type: text/plain; |
| charset="us-ascii" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: <pgsql-performance@postgresql.org> |
| Subject: Comparitive UPDATE speed |
| Date: Tue, 1 Oct 2002 14:51:29 -0700 |
| X-Mailer: KMail [version 1.4] |
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|
|
| Relative performance question: |
|
|
| I have 2 UPDATE queires in a function.=20 |
|
|
| table_a: 117,000 records |
| table_b: 117,000 records |
| table_c: 1.5 million records |
|
|
| |
| _3.=20 |
| Around 110,000 updates |
| |
| Around 110,000 updates. |
|
|
| |
| =20 |
| discern is that table_a, field_2 is indexed and table_a, field_5 is not. |
|
|
| Is it reasonable that updating the index would actually make the query take= |
| =20 |
| 20x longer? If not, I'll post actual table defs and query statements. |
| |
| --=20 |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 1 19:49:49 2002 |
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| for <pgsql-performance@postgresql.org>; |
| Tue, 1 Oct 2002 19:49:48 -0400 (EDT) |
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| with HTTP id 1736716; Tue, 01 Oct 2002 16:50:21 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Comparitive UPDATE speed |
| To: Randy Neumann <Randy_Neumann@centralref.com>, |
| pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Tue, 01 Oct 2002 16:50:21 -0700 |
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| |
| |
| Randy, |
| |
| > I'm not sure about 20 times longer but you would have index records |
| > that |
| > would need to be changed. Is field_3 indexed in all 3 tables? If |
| > table_b |
| > does not have an index on field_3 and the other tables do, I'd guess |
| > that |
| > would make this take longer too. |
| |
| Yeah, they're indexed. I'm going to try the updates without the index |
| on field_2 tonight. |
| |
| -Josh Berkus |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 2 06:50:03 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id F2D22475CA6 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 2 Oct 2002 06:50:02 -0400 (EDT) |
| Received: from lakemtao02.cox.net (lakemtao02.cox.net [68.1.17.243]) |
| by postgresql.org (Postfix) with ESMTP id 63884475C26 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 2 Oct 2002 06:50:02 -0400 (EDT) |
| Received: from localhost.localdomain ([68.11.66.83]) by lakemtao02.cox.net |
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| for <pgsql-performance@postgresql.org>; |
| Wed, 2 Oct 2002 06:50:05 -0400 |
| Subject: Re: Comparitive UPDATE speed |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <200210011451.29254.josh@agliodbs.com> |
| References: <200210011451.29254.josh@agliodbs.com> |
| Content-Type: text/plain |
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| Date: 02 Oct 2002 05:48:01 -0500 |
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| |
| On Tue, 2002-10-01 at 16:51, Josh Berkus wrote: |
| > Relative performance question: |
| > |
| > I have 2 UPDATE queires in a function. |
| > |
| > table_a: 117,000 records |
| > table_b: 117,000 records |
| > table_c: 1.5 million records |
| > |
| > #1 updates table_a, field_2 from table_b, field_1 based on a joining field_3. |
| > Around 110,000 updates |
| > #2 updates table_a, field_5 from table_c, field_2 joining on field_3. |
| > Around 110,000 updates. |
| > |
| > #1 takes 5-7 minutes; #2 takes about 15 seconds. The only difference I can |
| > discern is that table_a, field_2 is indexed and table_a, field_5 is not. |
| > |
| > Is it reasonable that updating the index would actually make the query take |
| > 20x longer? If not, I'll post actual table defs and query statements. |
|
|
| Absolutely. You are doing lots of extra work. |
|
|
| For each of the 110,000 updates, you are deleting a leaf node from one |
| part of the index tree and then inserting it into another part of the |
| tree. |
|
|
| It will get even worse as you add more rows to table_a, since the |
| index tree will get deeper, and more work work must be done during |
| each insert and delete. |
|
|
| |
| + |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "What other evidence do you have that they are terrorists, | |
| | other than that they trained in these camps?" | |
| | 17-Sep-2002 Katie Couric to an FBI agent regarding the 5 | |
| | men arrested near Buffalo NY | |
| + |
|
|
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 08:35:42 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 45BC5476237 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 08:35:40 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id 79B41476228 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 08:35:38 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 18:07:08 +0530 |
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| Thu, 3 Oct 2002 18:07:07 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org |
| Date: Thu, 03 Oct 2002 18:06:10 +0530 |
| MIME-Version: 1.0 |
| Content-type: Multipart/Mixed; boundary=Message-Boundary-2419 |
| Subject: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Message-ID: <3D9C8712.9513.9C6521D@localhost> |
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|
|
| |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Mail message body |
|
|
| Hi, |
|
|
| Today we concluded test for database performance. Attached are results and the |
| schema, for those who have missed earlier discussion on this. |
|
|
| We have (almost) decided that we will partition the data across machines. The |
| theme is, after every some short interval a burst of data will be entered in |
| new table in database, indexed and vacuume. The table(s) will be inherited so |
| that query on base table will fetch results from all the children. The |
| application has to consolidate all the data per node basis. If the database is |
| not postgresql, app. has to consolidate data across partitions as well. |
|
|
| Now we need to investigate whether selecting on base table to include children |
| would use indexes created on children table. |
|
|
| It's estimated that when entire data is gathered, total number of children |
| tables would be around 1K-1.1K across all machines. |
| |
| This is in point of average rate of data insertion i.e. 5K records/sec and |
| total data size, estimated to be 9 billion rows max i.e. estimated database |
| size is 900GB. Obviously it's impossible to keep insertion rate on an indexed |
| table high as data grows. So partitioning/inheritance looks better approach. |
|
|
| Postgresql is not the final winner as yet. Mysql is in close range. I will keep |
| you guys posted about the result. |
|
|
| Let me know about any comments.. |
|
|
| Bye |
| Shridhar |
|
|
| |
| Price's Advice: It's all a game |
|
|
|
|
|
|
| |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Text from file 'pgbenchmark.txt' |
|
|
| Machine |
| Compaq Proliant Server ML 530 |
| "Intel Xeon 2.4 Ghz Processor x 4, " |
| "4 GB RAM, 5 x 72.8 GB SCSI HDD " |
| "RAID 0 (Striping) Hardware Setup, Mandrake Linux 9.0" |
| "Cost - $13,500 ($1,350 for each additional 72GB HDD)" |
| |
| Performance Parameter MySQL 3.23.52 MySQL 3.23.52 PostgreSQL 7.2.2 |
| WITHOUT InnoDB WITH InnoDB for with built-in support |
| for transactional transactional support for transactions |
| support |
| Complete Data |
| |
| Inserts + building a composite index |
| "40 GB data, 432,000,000 tuples" 3738 secs 18720 secs 20628 secs |
| "about 100 bytes each, schema on |
| 'schema' sheet" |
| "composite index on 3 fields |
| (esn, min, datetime)" |
| |
| Load Speed 115570 tuples/second 23076 tuples/second 20942 tuples/second |
| |
| Database Size on Disk 48 GB 87 GB 111 GB |
| |
| Average per partition |
| |
| Inserts + building a composite index |
| "300MB data, 3,000,000 tuples," 28 secs 130 secs 150 secs |
| "about 100 bytes each, schema on |
| 'schema' sheet" |
| "composite index on 3 fields |
| (esn, min, datetime)" |
| |
| Select Query 7 secs 7 secs 6 secs |
| based on equality match of 2 fields |
| (esn and min) - 4 concurrent queries |
| running |
| |
| Database Size on Disk 341 MB 619 MB 788 MB |
|
|
| |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Text from file 'schema.txt' |
|
|
| Field Name Field Type Nullable Indexed |
| type int no no |
| esn char (10) no yes |
| min char (10) no yes |
| datetime timestamp no yes |
| opc0 char (3) no no |
| opc1 char (3) no no |
| opc2 char (3) no no |
| dpc0 char (3) no no |
| dpc1 char (3) no no |
| dpc2 char (3) no no |
| npa char (3) no no |
| nxx char (3) no no |
| rest char (4) no no |
| field0 int yes no |
| field1 char (4) yes no |
| field2 int yes no |
| field3 char (4) yes no |
| field4 int yes no |
| field5 char (4) yes no |
| field6 int yes no |
| field7 char (4) yes no |
| field8 int yes no |
| field9 char (4) yes no |
|
|
|
|
| |
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 08:54:34 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
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| Received: from clearmetrix.com (unknown [209.92.142.67]) |
| by postgresql.org (Postfix) with ESMTP |
| id 9462F476223; Thu, 3 Oct 2002 08:54:30 -0400 (EDT) |
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| forged)) |
| by clearmetrix.com (8.11.6/linuxconf) with ESMTP id g93CsQV11899; |
| Thu, 3 Oct 2002 08:54:26 -0400 |
| Message-ID: <3D9C3E05.7070906@clearmetrix.com> |
| Date: Thu, 03 Oct 2002 08:54:29 -0400 |
| From: "Charles H. Woloszynski" <chw@clearmetrix.com> |
| User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; |
| rv:1.1) Gecko/20020826 |
| X-Accept-Language: en-us, en |
| MIME-Version: 1.0 |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Subject: Re: Large databases, performance |
| References: <3D9C8712.9513.9C6521D@localhost> |
| Content-Type: text/plain; charset=ISO-8859-1; format=flowed |
| Content-Transfer-Encoding: 7bit |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/116 |
| X-Sequence-Number: 31115 |
|
|
| Can you comment on the tools you are using to do the insertions (Perl, |
| Java?) and the distribution of data (all random, all static), and the |
| transaction scope (all inserts in one transaction, each insert as a |
| single transaction, some group of inserts as a transaction). |
|
|
| I'd be curious what happens when you submit more queries than you have |
| processors (you had four concurrent queries and four CPUs), if you care |
| to run any additional tests. Also, I'd report the query time in |
| absolute (like you did) and also in 'Time/number of concurrent queries". |
| This will give you a sense of how the system is scaling as the workload |
| increases. Personally I am more concerned about this aspect than the |
| load time, since I am going to guess that this is where all the time is |
| spent. |
| |
| Was the original posting on GENERAL or HACKERS. Is this moving the |
| PERFORMANCE for follow-up? I'd like to follow this discussion and want |
| to know if I should join another group? |
|
|
| Thanks, |
|
|
| Charlie |
|
|
| P.S. Anyone want to comment on their expectation for 'commercial' |
| databases handling this load? I know that we cannot speak about |
| specific performance metrics on some products (licensing restrictions) |
| but I'd be curious if folks have seen some of the databases out there |
| handle these dataset sizes and respond resonably. |
| |
| |
| Shridhar Daithankar wrote: |
| |
| >Hi, |
| > |
| >Today we concluded test for database performance. Attached are results and the |
| >schema, for those who have missed earlier discussion on this. |
| > |
| >We have (almost) decided that we will partition the data across machines. The |
| >theme is, after every some short interval a burst of data will be entered in |
| >new table in database, indexed and vacuume. The table(s) will be inherited so |
| >that query on base table will fetch results from all the children. The |
| >application has to consolidate all the data per node basis. If the database is |
| >not postgresql, app. has to consolidate data across partitions as well. |
| > |
| >Now we need to investigate whether selecting on base table to include children |
| >would use indexes created on children table. |
| > |
| >It's estimated that when entire data is gathered, total number of children |
| >tables would be around 1K-1.1K across all machines. |
| > |
| >This is in point of average rate of data insertion i.e. 5K records/sec and |
| >total data size, estimated to be 9 billion rows max i.e. estimated database |
| >size is 900GB. Obviously it's impossible to keep insertion rate on an indexed |
| >table high as data grows. So partitioning/inheritance looks better approach. |
| > |
| >Postgresql is not the final winner as yet. Mysql is in close range. I will keep |
| >you guys posted about the result. |
| > |
| >Let me know about any comments.. |
| > |
| >Bye |
| > Shridhar |
| > |
| >-- |
| >Price's Advice: It's all a game -- play it to have fun. |
| > |
| > |
| > |
| > |
| >------------------------------------------------------------------------ |
| > |
| >Machine |
| >Compaq Proliant Server ML 530 |
| >"Intel Xeon 2.4 Ghz Processor x 4, " |
| >"4 GB RAM, 5 x 72.8 GB SCSI HDD " |
| >"RAID 0 (Striping) Hardware Setup, Mandrake Linux 9.0" |
| >"Cost - $13,500 ($1,350 for each additional 72GB HDD)" |
| > |
| >Performance Parameter MySQL 3.23.52 MySQL 3.23.52 PostgreSQL 7.2.2 |
| > WITHOUT InnoDB WITH InnoDB for with built-in support |
| > for transactional transactional support for transactions |
| > support |
| >Complete Data |
| > |
| >Inserts + building a composite index |
| >"40 GB data, 432,000,000 tuples" 3738 secs 18720 secs 20628 secs |
| >"about 100 bytes each, schema on |
| >'schema' sheet" |
| >"composite index on 3 fields |
| >(esn, min, datetime)" |
| > |
| >Load Speed 115570 tuples/second 23076 tuples/second 20942 tuples/second |
| > |
| >Database Size on Disk 48 GB 87 GB 111 GB |
| > |
| >Average per partition |
| > |
| >Inserts + building a composite index |
| >"300MB data, 3,000,000 tuples," 28 secs 130 secs 150 secs |
| >"about 100 bytes each, schema on |
| >'schema' sheet" |
| >"composite index on 3 fields |
| >(esn, min, datetime)" |
| > |
| >Select Query 7 secs 7 secs 6 secs |
| >based on equality match of 2 fields |
| >(esn and min) - 4 concurrent queries |
| >running |
| > |
| >Database Size on Disk 341 MB 619 MB 788 MB |
| > |
| > |
| >------------------------------------------------------------------------ |
| > |
| >Field Name Field Type Nullable Indexed |
| >type int no no |
| >esn char (10) no yes |
| >min char (10) no yes |
| >datetime timestamp no yes |
| >opc0 char (3) no no |
| >opc1 char (3) no no |
| >opc2 char (3) no no |
| >dpc0 char (3) no no |
| >dpc1 char (3) no no |
| >dpc2 char (3) no no |
| >npa char (3) no no |
| >nxx char (3) no no |
| >rest char (4) no no |
| >field0 int yes no |
| >field1 char (4) yes no |
| >field2 int yes no |
| >field3 char (4) yes no |
| >field4 int yes no |
| >field5 char (4) yes no |
| >field6 int yes no |
| >field7 char (4) yes no |
| >field8 int yes no |
| >field9 char (4) yes no |
| > |
| > |
| > |
| >------------------------------------------------------------------------ |
| > |
| > |
| >---------------------------(end of broadcast)--------------------------- |
| >TIP 2: you can get off all lists at once with the unregister command |
| > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) |
| > |
| > |
| |
| -- |
| |
| |
| Charles H. Woloszynski |
| |
| ClearMetrix, Inc. |
| 115 Research Drive |
| Bethlehem, PA 18015 |
| |
| tel: 610-419-2210 x400 |
| fax: 240-371-3256 |
| web: www.clearmetrix.com |
| |
| |
| |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 08:56:02 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 759394762F8 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 08:56:01 -0400 (EDT) |
| Received: from smtp.investsystems.co.uk (unknown [62.49.196.163]) |
| by postgresql.org (Postfix) with SMTP id 5512347625C |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 08:56:00 -0400 (EDT) |
| Received: (qmail 61099 invoked from network); 3 Oct 2002 12:56:03 -0000 |
| Received: from ponder.fairway2k.co.uk (nandrews@172.31.1.3) |
| by hex.fairway2k.co.uk with SMTP; 3 Oct 2002 12:56:03 -0000 |
| Date: Thu, 3 Oct 2002 13:56:03 +0100 (BST) |
| From: "Nigel J. Andrews" <nandrews@investsystems.co.uk> |
| X-Sender: nandrews@ponder.fairway2k.co.uk |
| To: Shridhar Daithankar <shridhar_daithankar@persistent.co.in> |
| Cc: pgsql-general <pgsql-general@postgresql.org> |
| Subject: Re: Large databases, performance |
| In-Reply-To: <3D9C8712.9513.9C6521D@localhost> |
| Message-ID: <Pine.LNX.4.21.0210031353540.26902-100000@ponder.fairway2k.co.uk> |
| MIME-Version: 1.0 |
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| X-Sequence-Number: 31116 |
| |
| |
| Shridhar, |
| |
| It's one hell of a DB you're building. I'm sure I'm not the only one interested |
| so to satisfy those of us who are nosey: can you say what the application is? |
| |
| I'm sure we'll all understand if it's not possible for you mention such |
| information. |
|
|
|
|
| |
| Nigel J. Andrews |
|
|
|
|
| On Thu, 3 Oct 2002, Shridhar Daithankar wrote: |
|
|
| > Hi, |
| > |
| > Today we concluded test for database performance. Attached are results and the |
| > schema, for those who have missed earlier discussion on this. |
| > |
| > We have (almost) decided that we will partition the data across machines. The |
| > theme is, after every some short interval a burst of data will be entered in |
| > new table in database, indexed and vacuume. The table(s) will be inherited so |
| > that query on base table will fetch results from all the children. The |
| > application has to consolidate all the data per node basis. If the database is |
| > not postgresql, app. has to consolidate data across partitions as well. |
| > |
| > Now we need to investigate whether selecting on base table to include children |
| > would use indexes created on children table. |
| > |
| > It's estimated that when entire data is gathered, total number of children |
| > tables would be around 1K-1.1K across all machines. |
| > |
| > This is in point of average rate of data insertion i.e. 5K records/sec and |
| > total data size, estimated to be 9 billion rows max i.e. estimated database |
| > size is 900GB. Obviously it's impossible to keep insertion rate on an indexed |
| > table high as data grows. So partitioning/inheritance looks better approach. |
| > |
| > Postgresql is not the final winner as yet. Mysql is in close range. I will keep |
| > you guys posted about the result. |
| > |
| > Let me know about any comments.. |
| > |
| > Bye |
| > Shridhar |
|
|
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 10:03:00 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 3AC1A475C22 |
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| Thu, 3 Oct 2002 10:02:59 -0400 (EDT) |
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| Thu, 3 Oct 2002 10:02:57 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 19:34:27 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-general <pgsql-general@postgresql.org> |
| Date: Thu, 03 Oct 2002 19:33:30 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3D9C9B8A.30310.A16469F@localhost> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| In-reply-to: <Pine.LNX.4.21.0210031353540.26902-100000@ponder.fairway2k.co.uk> |
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|
|
| On 3 Oct 2002 at 13:56, Nigel J. Andrews wrote: |
| > It's one hell of a DB you're building. I'm sure I'm not the only one interested |
| > so to satisfy those of us who are nosey: can you say what the application is? |
| > |
| > I'm sure we'll all understand if it's not possible for you mention such |
| > information. |
| |
| Well, I can't tell everything but somethings I can.. |
|
|
| 1) This is a system that does not have online capability yet. This is an |
| attempt to provide one. |
|
|
| 2) The goal is to avoid costs like licensing oracle. I am sure this would make |
| a great example for OSDB advocacy, which ever database wins.. |
|
|
| 3) The database size estimates, I put earlier i.e. 9 billion tuples/900GB data |
| size, are in a fixed window. The data is generated from some real time systems. |
| You can imagine the rate. |
|
|
| 4) Further more there are timing restrictions attached to it. 5K inserts/sec. |
| 4800 queries per hour with response time of 10 sec. each. It's this aspect that |
| has forced us for partitioning.. |
| |
| And contrary to my earlier information, this is going to be a live system |
| rather than a back up one.. A better win to postgresql.. I hope it makes it. |
| |
| And BTW, all these results were on reiserfs. We didn't found much of difference |
| in write performance between them. So we stick to reiserfs. And of course we |
| got the latest hot shot Mandrake9 with 2.4.19-16 which really made difference |
| over RHL7.2.. |
|
|
| Bye |
| Shridhar |
|
|
| |
| QOTD: "Do you smell something burning or is it me?" |
|
|
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 10:27:03 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 00D77475E82 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 10:27:02 -0400 (EDT) |
| Received: from clearmetrix.com (unknown [209.92.142.67]) |
| by postgresql.org (Postfix) with ESMTP id 4C84D475C9E |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 10:27:01 -0400 (EDT) |
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| forged)) |
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| Thu, 3 Oct 2002 10:27:00 -0400 |
| Message-ID: <3D9C53B3.2050508@clearmetrix.com> |
| Date: Thu, 03 Oct 2002 10:26:59 -0400 |
| From: "Charles H. Woloszynski" <chw@clearmetrix.com> |
| X-Accept-Language: en-us, en |
| MIME-Version: 1.0 |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-general <pgsql-general@postgresql.org> |
| Subject: Re: Large databases, performance |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9C9B8A.30310.A16469F@localhost> |
| Content-Type: text/plain; charset=ISO-8859-1; format=flowed |
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|
|
| Forgive my ignorance, but what about 2.4.19-16 is that much faster? Are |
| we talking about 2x improvement for your tests? We are currently on |
| 2.4.9 and looking at the performance and wondering... so any comments |
| are appreciated. |
|
|
| Charlie |
|
|
|
|
| Shridhar Daithankar wrote: |
|
|
| >And BTW, all these results were on reiserfs. We didn't found much of difference |
| >in write performance between them. So we stick to reiserfs. And of course we |
| >got the latest hot shot Mandrake9 with 2.4.19-16 which really made difference |
| >over RHL7.2.. |
| > |
| >Bye |
| > Shridhar |
| > |
| >-- |
| >QOTD: "Do you smell something burning or is it me?" -- Joan of Arc |
| > |
| > |
| >---------------------------(end of broadcast)--------------------------- |
| >TIP 5: Have you checked our extensive FAQ? |
| > |
| >http://www.postgresql.org/users-lounge/docs/faq.html |
| > |
| > |
| |
| -- |
| |
| |
| Charles H. Woloszynski |
| |
| ClearMetrix, Inc. |
| 115 Research Drive |
| Bethlehem, PA 18015 |
| |
| tel: 610-419-2210 x400 |
| fax: 240-371-3256 |
| web: www.clearmetrix.com |
| |
| |
| |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 11:49:44 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 6EFF2475D12 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 11:49:43 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id EFE17475C15 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 11:49:41 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 21:21:13 +0530 |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 21:21:13 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-general <pgsql-general@postgresql.org> |
| Date: Thu, 03 Oct 2002 21:20:16 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3D9CB490.2412.A78039E@localhost> |
| In-reply-to: <3D9C53B3.2050508@clearmetrix.com> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
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| X-Archive-Number: 200210/125 |
| X-Sequence-Number: 31124 |
| |
| On 3 Oct 2002 at 10:26, Charles H. Woloszynski wrote: |
| |
| > Forgive my ignorance, but what about 2.4.19-16 is that much faster? Are |
| > we talking about 2x improvement for your tests? We are currently on |
| > 2.4.9 and looking at the performance and wondering... so any comments |
| > are appreciated. |
| |
| Well, for one thing, 2.4.19 contains backported O(1) scheduler patch which |
| improves SMP performance by heaps as task queue is per cpu rather than one per |
| system. I don't think any system routinely runs thousands of processes unless |
| it's a web/ftp/mail server. In that case improved scheduling wuld help as |
| well.. |
| |
| Besides there were major VM rewrites/changes after 2.4.10 which corrected |
| almost all the major VM fiaskos on linux. For anything VM intensive it's |
| recommended that you run 2.4.17 at least. |
|
|
| I would say it's worth going for it. |
| |
| Bye |
| Shridhar |
| |
| -- |
| Sturgeon's Law: 90% of everything is crud. |
|
|
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 11:56:15 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 260004767C0 |
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| Thu, 3 Oct 2002 11:56:13 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 50F1D476759 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 11:56:11 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 21:27:41 +0530 |
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| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g93Fvfv04044; |
| Thu, 3 Oct 2002 21:27:41 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-general <pgsql-general@postgresql.org> |
| Date: Thu, 03 Oct 2002 21:26:43 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org |
| Message-ID: <3D9CB613.1700.A7DEEF0@localhost> |
| In-reply-to: <3D9C9B8A.30310.A16469F@localhost> |
| References: <Pine.LNX.4.21.0210031353540.26902-100000@ponder.fairway2k.co.uk> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
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| X-Archive-Number: 200210/126 |
| X-Sequence-Number: 31125 |
|
|
| On 3 Oct 2002 at 19:33, Shridhar Daithankar wrote: |
|
|
| > On 3 Oct 2002 at 13:56, Nigel J. Andrews wrote: |
| > > It's one hell of a DB you're building. I'm sure I'm not the only one interested |
| > > so to satisfy those of us who are nosey: can you say what the application is? |
| > > |
| > > I'm sure we'll all understand if it's not possible for you mention such |
| > > information. |
| > |
| > Well, I can't tell everything but somethings I can.. |
| > |
| > 1) This is a system that does not have online capability yet. This is an |
| > attempt to provide one. |
| > |
| > 2) The goal is to avoid costs like licensing oracle. I am sure this would make |
| > a great example for OSDB advocacy, which ever database wins.. |
| > |
| > 3) The database size estimates, I put earlier i.e. 9 billion tuples/900GB data |
| > size, are in a fixed window. The data is generated from some real time systems. |
| > You can imagine the rate. |
|
|
| Read that fixed time window.. |
|
|
| > |
| > 4) Further more there are timing restrictions attached to it. 5K inserts/sec. |
| > 4800 queries per hour with response time of 10 sec. each. It's this aspect that |
| > has forced us for partitioning.. |
| > |
| > And contrary to my earlier information, this is going to be a live system |
| > rather than a back up one.. A better win to postgresql.. I hope it makes it. |
| > |
| > And BTW, all these results were on reiserfs. We didn't found much of difference |
| > in write performance between them. So we stick to reiserfs. And of course we |
| > got the latest hot shot Mandrake9 with 2.4.19-16 which really made difference |
| > over RHL7.2.. |
|
|
| Well, we were comparing ext3 v/s reiserfs. I don't remember the journalling |
| mode of ext3 but we did a 10 GB write test. Besides converting the RAID to RAID- |
| 0 from RAID-5 might have something to do about it. |
| |
| There was a discussion on hackers some time back as in which file system is |
| better. I hope this might have an addition over it.. |
| |
| |
| Bye |
| Shridhar |
| |
| -- |
| "What terrible way to die." "There are no good ways." -- Sulu and Kirk, "That |
| Which Survives", stardate unknown |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:01:42 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
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| Received: from briar.mmrd.com (unknown [208.255.226.182]) |
| by postgresql.org (Postfix) with ESMTP |
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| (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) |
| id TK2FXAW3; Thu, 3 Oct 2002 12:01:34 -0400 |
| Subject: Re: Large databases, performance |
| From: Robert Treat <xzilla@users.sourceforge.net> |
| Reply-To: pgsql-performance@postgresql.org |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| In-Reply-To: <3D9C8712.9513.9C6521D@localhost> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 03 Oct 2002 11:57:29 -0400 |
| Message-Id: <1033660649.21324.53.camel@camel> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/128 |
| X-Sequence-Number: 31127 |
| |
| NOTE: Setting follow up to the performance list |
| |
| Funny that the status quo seems to be if you need fast selects on data |
| that has few inserts to pick mysql, otherwise if you have a lot of |
| inserts and don't need super fast selects go with PostgreSQL; yet your |
| data seems to cut directly against this. |
|
|
| I'm curious, did you happen to run the select tests while also running |
| the insert tests? IIRC the older mysql versions have to lock the table |
| when doing the insert, so select performance goes in the dumper in that |
| scenario, perhaps that's not an issue with 3.23.52? |
|
|
| It also seems like the vacuum after each insert is unnecessary, unless |
| your also deleting/updating data behind it. Perhaps just running an |
| ANALYZE on the table would suffice while reducing overhead. |
|
|
| Robert Treat |
|
|
| On Thu, 2002-10-03 at 08:36, Shridhar Daithankar wrote: |
| > Machine |
| > Compaq Proliant Server ML 530 |
| > "Intel Xeon 2.4 Ghz Processor x 4, " |
| > "4 GB RAM, 5 x 72.8 GB SCSI HDD " |
| > "RAID 0 (Striping) Hardware Setup, Mandrake Linux 9.0" |
| > "Cost - $13,500 ($1,350 for each additional 72GB HDD)" |
| > |
| > Performance Parameter MySQL 3.23.52 MySQL 3.23.52 PostgreSQL 7.2.2 |
| > WITHOUT InnoDB WITH InnoDB for with built-in support |
| > for transactional transactional support for transactions |
| > support |
| > Complete Data |
| > |
| > Inserts + building a composite index |
| > "40 GB data, 432,000,000 tuples" 3738 secs 18720 secs 20628 secs |
| > "about 100 bytes each, schema on |
| > 'schema' sheet" |
| > "composite index on 3 fields |
| > (esn, min, datetime)" |
| > |
| > Load Speed 115570 tuples/second 23076 tuples/second 20942 tuples/second |
| > |
| > Database Size on Disk 48 GB 87 GB 111 GB |
| > |
| > Average per partition |
| > |
| > Inserts + building a composite index |
| > "300MB data, 3,000,000 tuples," 28 secs 130 secs 150 secs |
| > "about 100 bytes each, schema on |
| > 'schema' sheet" |
| > "composite index on 3 fields |
| > (esn, min, datetime)" |
| > |
| > Select Query 7 secs 7 secs 6 secs |
| > based on equality match of 2 fields |
| > (esn and min) - 4 concurrent queries |
| > running |
| > |
| > Database Size on Disk 341 MB 619 MB 788 MB |
| > |
|
|
|
|
|
|
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:07:27 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 75AB4476A9F |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:07:24 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id A6610476A98 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:07:22 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 21:38:52 +0530 |
| Received: from daithan (daithan.intranet.pspl.co.in [192.168.7.161]) |
| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g93G8qv04675; |
| Thu, 3 Oct 2002 21:38:52 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, pgsql-general <pgsql-general@postgresql.org> |
| Date: Thu, 03 Oct 2002 21:37:55 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3D9CB8B3.25411.A882D21@localhost> |
| In-reply-to: <3D9C3E05.7070906@clearmetrix.com> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
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|
|
| On 3 Oct 2002 at 8:54, Charles H. Woloszynski wrote: |
|
|
| > Can you comment on the tools you are using to do the insertions (Perl, |
| > Java?) and the distribution of data (all random, all static), and the |
| > transaction scope (all inserts in one transaction, each insert as a |
| > single transaction, some group of inserts as a transaction). |
|
|
| Most proably it's all inserts in one transaction spread almost uniformly over |
| around 15-20 tables. Of course there will be bunch of transactions.. |
| |
| > I'd be curious what happens when you submit more queries than you have |
| > processors (you had four concurrent queries and four CPUs), if you care |
| > to run any additional tests. Also, I'd report the query time in |
| > absolute (like you did) and also in 'Time/number of concurrent queries". |
| > This will give you a sense of how the system is scaling as the workload |
| > increases. Personally I am more concerned about this aspect than the |
| > load time, since I am going to guess that this is where all the time is |
| > spent. |
| |
| I don't think so. Because we plan to put enough shared buffers that would |
| almost contain the indexes in RAM if not data. Besides number of tuples |
| expected per query are not many. So more concurrent queries are not going to |
| hog anything other than CPU power at most. |
| |
| Our major concern remains load time as data is generated in real time and is |
| expecetd in database with in specified time period. We need indexes for query |
| and inserting into indexed table is on hell of a job. We did attempt inserting |
| 8GB of data in indexed table. It took almost 20 hours at 1K tuples per second |
| on average.. Though impressive it's not acceptable for that load.. |
| > |
| > Was the original posting on GENERAL or HACKERS. Is this moving the |
| > PERFORMANCE for follow-up? I'd like to follow this discussion and want |
| > to know if I should join another group? |
| |
| Shall I subscribe to performance? What's the exat list name? Benchmarks? I |
| don't see anything as performance mailing list on this page.. |
| http://developer.postgresql.org/mailsub.php?devlp |
| |
| > P.S. Anyone want to comment on their expectation for 'commercial' |
| > databases handling this load? I know that we cannot speak about |
| > specific performance metrics on some products (licensing restrictions) |
| > but I'd be curious if folks have seen some of the databases out there |
| > handle these dataset sizes and respond resonably. |
| |
| Well, if something handles such kind of data with single machine and costs |
| under USD20K for entire setup, I would be willing to recommend that to client.. |
| |
| BTW we are trying same test on HP-UX. I hope we get some better figures on 64 |
| bit machines.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| Clarke's Conclusion: Never let your sense of morals interfere with doing the |
| right thing. |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:16:12 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 6A4E54766BA; Thu, 3 Oct 2002 12:16:11 -0400 (EDT) |
| Received: from new-smtp2.ihug.com.au (new-smtp2.ihug.com.au [203.109.250.28]) |
| by postgresql.org (Postfix) with ESMTP |
| id 88893476606; Thu, 3 Oct 2002 12:16:10 -0400 (EDT) |
| Received: from p286-tnt1.mel.ihug.com.au (postgresql.org) [203.173.161.32] |
| by new-smtp2.ihug.com.au with esmtp (Exim 3.22 #1 (Debian)) |
| id 17x8e0-0002c2-00; Fri, 04 Oct 2002 02:16:09 +1000 |
| Message-ID: <3D9C6D46.CCDB3047@postgresql.org> |
| Date: Fri, 04 Oct 2002 02:16:06 +1000 |
| From: Justin Clift <justin@postgresql.org> |
| X-Mailer: Mozilla 4.79 [en] (WinNT; U) |
| X-Accept-Language: en |
| MIME-Version: 1.0 |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, pgsql-general <pgsql-general@postgresql.org> |
| Subject: Re: [HACKERS] Large databases, performance |
| References: <3D9CB8B3.25411.A882D21@localhost> |
| Content-Type: text/plain; charset=us-ascii |
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| |
| Shridhar Daithankar wrote: |
| <snip> |
| > > Was the original posting on GENERAL or HACKERS. Is this moving the |
| > > PERFORMANCE for follow-up? I'd like to follow this discussion and want |
| > > to know if I should join another group? |
| > |
| > Shall I subscribe to performance? What's the exat list name? Benchmarks? I |
| > don't see anything as performance mailing list on this page.. |
| > http://developer.postgresql.org/mailsub.php?devlp |
| |
| It's a fairly new mailing list. :) |
| |
| pgsql-performance@postgresql.org |
| |
| Easiest way to subscribe is by emailing majordomo@postgresql.org with: |
| |
| subscribe pgsql-performance |
| |
| as the message body. |
| |
| :-) |
| |
| Regards and best wishes, |
| |
| Justin Clift |
| |
| <snip> |
| > Bye |
| > Shridhar |
| > |
| > -- |
| > Clarke's Conclusion: Never let your sense of morals interfere with doing the |
| > right thing. |
| > |
| > ---------------------------(end of broadcast)--------------------------- |
| > TIP 2: you can get off all lists at once with the unregister command |
| > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) |
| |
| -- |
| "My grandfather once told me that there are two kinds of people: those |
| who work and those who take the credit. He told me to try to be in the |
| first group; there was less competition there." |
| - Indira Gandhi |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:16:51 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 3DDFC476B00 |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:16:50 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 4CDE247675B |
| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:16:29 -0400 (EDT) |
| Received: (from root@localhost) |
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| for <pgsql-general@postgresql.org>; Thu, 3 Oct 2002 21:48:01 +0530 |
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| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g93GI1v05269; |
| Thu, 3 Oct 2002 21:48:01 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Date: Thu, 03 Oct 2002 21:47:03 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3D9CBAD7.23509.A908C61@localhost> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| In-reply-to: <1033660649.21324.53.camel@camel> |
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| |
| On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| |
| > NOTE: Setting follow up to the performance list |
| > |
| > Funny that the status quo seems to be if you need fast selects on data |
| > that has few inserts to pick mysql, otherwise if you have a lot of |
| > inserts and don't need super fast selects go with PostgreSQL; yet your |
| > data seems to cut directly against this. |
| |
| Well, couple of things.. |
| |
| The number of inserts aren't few. it's 5000/sec.required in the field Secondly |
| I don't know really but postgresql seems doing pretty fine in parallel selects. |
| If we use mysql with transaction support then numbers are really close.. |
| |
| May be it's time to rewrite famous myth that postgresql is slow. When properly |
| tuned or given enough head room, it's almost as fast as mysql.. |
| |
| > I'm curious, did you happen to run the select tests while also running |
| > the insert tests? IIRC the older mysql versions have to lock the table |
| > when doing the insert, so select performance goes in the dumper in that |
| > scenario, perhaps that's not an issue with 3.23.52? |
| |
| IMO even if it locks tables that shouldn't affect select performance. It would |
| be fun to watch when we insert multiple chunks of data and fire queries |
| concurrently. I would be surprised if mysql starts slowing down.. |
| |
| > It also seems like the vacuum after each insert is unnecessary, unless |
| > your also deleting/updating data behind it. Perhaps just running an |
| > ANALYZE on the table would suffice while reducing overhead. |
| |
| I believe that was vacuum analyze only. But still it takes lot of time. Good |
| thing is it's not blocking.. |
| |
| Anyway I don't think such frequent vacuums are going to convince planner to |
| choose index scan over sequential scan. I am sure it's already convinced.. |
| |
| Regards, |
| Shridhar |
| |
| ----------------------------------------------------------- |
| Shridhar Daithankar |
| LIMS CPE Team Member, PSPL. |
| mailto:shridhar_daithankar@persistent.co.in |
| Phone:- +91-20-5678900 Extn.270 |
| Fax :- +91-20-5678901 |
| ----------------------------------------------------------- |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:23:40 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 96B8E475B8C; Thu, 3 Oct 2002 12:23:39 -0400 (EDT) |
| Received: from CopelandConsulting.Net (dsl-24293-ld.customer.centurytel.net |
| [209.142.135.135]) by postgresql.org (Postfix) with ESMTP |
| id A04A547674F; Thu, 3 Oct 2002 12:23:37 -0400 (EDT) |
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| [192.168.1.2]) |
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| Thu, 3 Oct 2002 11:23:23 -0500 (CDT) |
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| 3 Oct 2002 11:23:23 -0500 |
| (CDT).200210031623.g93GNMd20304.g93GNMd20304@CopelandConsulting.Net. |
| Subject: Re: [HACKERS] Large databases, performance |
| From: Greg Copeland <greg@CopelandConsulting.Net> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-general <pgsql-general@postgresql.org>, |
| PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org> |
| In-Reply-To: <3D9CB613.1700.A7DEEF0@localhost> |
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| <3D9CB613.1700.A7DEEF0@localhost> |
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| |
| On Thu, 2002-10-03 at 10:56, Shridhar Daithankar wrote: |
| > Well, we were comparing ext3 v/s reiserfs. I don't remember the journalli= |
| ng=20 |
| > mode of ext3 but we did a 10 GB write test. Besides converting the RAID t= |
| o RAID- |
| > 0 from RAID-5 might have something to do about it. |
| >=20 |
| > There was a discussion on hackers some time back as in which file system = |
| is=20 |
| > better. I hope this might have an addition over it.. |
| |
| |
| Hmm. Reiserfs' claim to fame is it's low latency with many, many small |
| files and that it's journaled. I've never seem anyone comment about it |
| being considered an extremely fast file system in an general computing |
| context nor have I seen any even hint at it as a file system for use in |
| heavy I/O databases. This is why Reiserfs is popular with news and |
| squid cache servers as it's almost an ideal fit. That is, tons of small |
| files or directories contained within a single directory. As such, I'm |
| very surprised that reiserfs is even in the running for your comparison. |
| |
| Might I point you toward XFS, JFS, or ext3, ? As I understand it, XFS |
| and JFS are going to be your preferred file systems for for this type of |
| application with XFS in the lead as it's tool suite is very rich and |
| robust. I'm actually lacking JFS experience but from what I've read, |
| it's a notch or two back from XFS in robustness (assuming we are talking |
| Linux here). Feel free to read and play to find out for your self. I'd |
| recommend that you start playing with XFS to see how the others |
| compare. After all, XFS' specific claim to fame is high throughput w/ |
| low latency on large and very large files. Furthermore, they even have |
| a real time mechanism that you can further play with to see how it |
| effects your throughput and/or latencies. |
| |
| Greg |
| |
| |
| |
| |
| --=-UufspPzcV77dAnLY19zJ |
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| From pgsql-performance-owner@postgresql.org Thu Oct 3 12:30:36 2002 |
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| id TK2FXA5P; Thu, 3 Oct 2002 12:30:38 -0400 |
| Subject: Re: Large databases, performance |
| From: Robert Treat <xzilla@users.sourceforge.net> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-performance@postgresql.org |
| In-Reply-To: <3D9CBAD7.23509.A908C61@localhost> |
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| On Thu, 2002-10-03 at 12:17, Shridhar Daithankar wrote: |
| > On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| > May be it's time to rewrite famous myth that postgresql is slow. |
| |
| That myth has been dis-proven long ago, it just takes awhile for |
| everyone to catch on ;-) |
| |
| When properly |
| > tuned or given enough head room, it's almost as fast as mysql.. |
| > |
| > > I'm curious, did you happen to run the select tests while also running |
| > > the insert tests? IIRC the older mysql versions have to lock the table |
| > > when doing the insert, so select performance goes in the dumper in that |
| > > scenario, perhaps that's not an issue with 3.23.52? |
| > |
| > IMO even if it locks tables that shouldn't affect select performance. It would |
| > be fun to watch when we insert multiple chunks of data and fire queries |
| > concurrently. I would be surprised if mysql starts slowing down.. |
| > |
| |
| Hmm... been awhile since I dug into mysql internals, but IIRC once the |
| table was locked, you had to wait for the insert to complete so the |
| table would be unlocked and the select could go through. (maybe this is |
| a myth that I need to get clued in on) |
| |
| > > It also seems like the vacuum after each insert is unnecessary, unless |
| > > your also deleting/updating data behind it. Perhaps just running an |
| > > ANALYZE on the table would suffice while reducing overhead. |
| > |
| > I believe that was vacuum analyze only. But still it takes lot of time. Good |
| > thing is it's not blocking.. |
| > |
| > Anyway I don't think such frequent vacuums are going to convince planner to |
| > choose index scan over sequential scan. I am sure it's already convinced.. |
| > |
| |
| My thinking was that if your just doing inserts, you need to update the |
| statistics but don't need to check on unused tuples. |
| |
| Robert Treat |
| |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 12:29:19 2002 |
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| for pgsql-performance@postgresql.org; Thu, 03 Oct 2002 09:29:21 -0700 |
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| From: Mike Benoit <mikeb@netnation.com> |
| To: pgsql-performance@postgresql.org |
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| subscribe pgsql-performance |
| |
| -- |
| Best Regards, |
| |
| Mike Benoit |
| NetNation Communication Inc. |
| Systems Engineer |
| Tel: 604-684-6892 or 888-983-6600 |
| --------------------------------------- |
| |
| Disclaimer: Opinions expressed here are my own and not |
| necessarily those of my employer |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:29:48 2002 |
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| Thu, 3 Oct 2002 22:01:16 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: Greg Copeland <greg@copelandconsulting.net> |
| Date: Thu, 03 Oct 2002 22:00:18 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [HACKERS] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-general <pgsql-general@postgresql.org>, |
| PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Message-ID: <3D9CBDF2.27020.A9CACCF@localhost> |
| References: <3D9CB613.1700.A7DEEF0@localhost> |
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| |
| On 3 Oct 2002 at 11:23, Greg Copeland wrote: |
| |
| > On Thu, 2002-10-03 at 10:56, Shridhar Daithankar wrote: |
| > > Well, we were comparing ext3 v/s reiserfs. I don't remember the journalling |
| > > mode of ext3 but we did a 10 GB write test. Besides converting the RAID to RAID- |
| > > 0 from RAID-5 might have something to do about it. |
| > > |
| > > There was a discussion on hackers some time back as in which file system is |
| > > better. I hope this might have an addition over it.. |
| > |
| > |
| > Hmm. Reiserfs' claim to fame is it's low latency with many, many small |
| > files and that it's journaled. I've never seem anyone comment about it |
| > being considered an extremely fast file system in an general computing |
| > context nor have I seen any even hint at it as a file system for use in |
| > heavy I/O databases. This is why Reiserfs is popular with news and |
| > squid cache servers as it's almost an ideal fit. That is, tons of small |
| > files or directories contained within a single directory. As such, I'm |
| > very surprised that reiserfs is even in the running for your comparison. |
| > |
| > Might I point you toward XFS, JFS, or ext3, ? As I understand it, XFS |
| > and JFS are going to be your preferred file systems for for this type of |
| > application with XFS in the lead as it's tool suite is very rich and |
| > robust. I'm actually lacking JFS experience but from what I've read, |
| > it's a notch or two back from XFS in robustness (assuming we are talking |
| > Linux here). Feel free to read and play to find out for your self. I'd |
| > recommend that you start playing with XFS to see how the others |
| > compare. After all, XFS' specific claim to fame is high throughput w/ |
| > low latency on large and very large files. Furthermore, they even have |
| > a real time mechanism that you can further play with to see how it |
| > effects your throughput and/or latencies. |
| |
| I would try that. Once we are thr. with tests at our hands.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| "The combination of a number of things to make existence worthwhile." "Yes, |
| the philosophy of 'none,' meaning 'all.'" -- Spock and Lincoln, "The Savage |
| Curtain", stardate 5906.4 |
| |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 12:34:53 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Thu, 3 Oct 2002 12:34:52 -0400 (EDT) |
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| Thu, 3 Oct 2002 22:06:21 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-performance@postgresql.org |
| Date: Thu, 03 Oct 2002 22:05:24 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Cc: "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Message-ID: <3D9CBF24.4516.AA1560C@localhost> |
| References: <3D9CBAD7.23509.A908C61@localhost> |
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| |
| On 3 Oct 2002 at 12:26, Robert Treat wrote: |
| |
| > On Thu, 2002-10-03 at 12:17, Shridhar Daithankar wrote: |
| > > On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| > > May be it's time to rewrite famous myth that postgresql is slow. |
| > |
| > That myth has been dis-proven long ago, it just takes awhile for |
| > everyone to catch on ;-) |
| |
| :-) |
| |
| > Hmm... been awhile since I dug into mysql internals, but IIRC once the |
| > table was locked, you had to wait for the insert to complete so the |
| > table would be unlocked and the select could go through. (maybe this is |
| > a myth that I need to get clued in on) |
| |
| If that turns out to be true, I guess mysql will nose dive out of window.. May |
| be time to run a test that's nearer to real world expectation, especially in |
| terms on concurrency.. |
| |
| I don't think tat will be an issue with mysql with transaction support. The |
| vanilla one might suffer.. Not the other one.. At least theoretically.. |
| |
| > My thinking was that if your just doing inserts, you need to update the |
| > statistics but don't need to check on unused tuples. |
| |
| Any other way of doing that other than vacuum analyze? I thought that was the |
| only way.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| "Even more amazing was the realization that God has Internet access. Iwonder |
| if He has a full newsfeed?"(By Matt Welsh) |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:43:03 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Thu, 3 Oct 2002 12:43:01 -0400 (EDT) |
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| by postgresql.org (Postfix) with SMTP id E4F704769D2 |
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| Thu, 3 Oct 2002 12:42:52 -0400 (EDT) |
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| for <shridhar?daithankar@persistent.co.in>; 3 Oct 2002 16:41:49 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Subject: Re: Large databases, performance |
| Date: Thu, 03 Oct 2002 18:44:09 +0200 |
| Message-ID: <onsopucciqfacce3mdnn0frv0tnnb54kui@4ax.com> |
| References: <3D9C8712.9513.9C6521D@localhost> |
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| |
| On Thu, 03 Oct 2002 18:06:10 +0530, "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> wrote: |
| >Machine |
| >Compaq Proliant Server ML 530 |
| >"Intel Xeon 2.4 Ghz Processor x 4, " |
| >"4 GB RAM, 5 x 72.8 GB SCSI HDD " |
| >"RAID 0 (Striping) Hardware Setup, Mandrake Linux 9.0" |
| |
| Shridhar, |
| |
| forgive me if I ask what has been said before: Did you run at 100% |
| CPU or was IO bandwidth your limit? And is the answer the same for |
| all three configurations? |
| |
| Servus |
| Manfred |
| |
| From pgsql-general-owner@postgresql.org Fri Oct 4 09:10:05 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:45:10 -0400 (EDT) |
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| for <pgsql-general@postgresql.org>; |
| Thu, 3 Oct 2002 12:45:08 -0400 (EDT) |
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| Date: Thu, 03 Oct 2002 18:51:05 +0200 |
| From: =?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <postgres@cybertec.at> |
| Reply-To: hs@cybertec.at |
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| To: shridhar_daithankar@persistent.co.in, |
| pgsql-performance@postgresql.org, pgsql-general@postgresql.org |
| Subject: Re: [HACKERS] Large databases, performance |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9CBAD7.23509.A908C61@localhost> |
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| |
| Shridhar Daithankar wrote: |
| |
| >On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| > |
| > |
| > |
| >>NOTE: Setting follow up to the performance list |
| >> |
| >>Funny that the status quo seems to be if you need fast selects on data |
| >>that has few inserts to pick mysql, otherwise if you have a lot of |
| >>inserts and don't need super fast selects go with PostgreSQL; yet your |
| >>data seems to cut directly against this. |
| >> |
| >> |
| > |
| >Well, couple of things.. |
| > |
| >The number of inserts aren't few. it's 5000/sec.required in the field Secondly |
| >I don't know really but postgresql seems doing pretty fine in parallel selects. |
| >If we use mysql with transaction support then numbers are really close.. |
| > |
| >May be it's time to rewrite famous myth that postgresql is slow. When properly |
| >tuned or given enough head room, it's almost as fast as mysql.. |
| > |
| > |
| |
| In the case of concurrent transactions MySQL does not do as well due to |
| very bad locking behavious. PostgreSQL is far better because it does row |
| level locking instead of table locking. |
| If you have many concurrent transactions MySQL performs some sort of |
| "self-denial-of-service". I'd choose PostgreSQL in order to make sure |
| that the database does not block. |
| |
| |
| >>I'm curious, did you happen to run the select tests while also running |
| >>the insert tests? IIRC the older mysql versions have to lock the table |
| >>when doing the insert, so select performance goes in the dumper in that |
| >>scenario, perhaps that's not an issue with 3.23.52? |
| >> |
| >> |
| > |
| >IMO even if it locks tables that shouldn't affect select performance. It would |
| >be fun to watch when we insert multiple chunks of data and fire queries |
| >concurrently. I would be surprised if mysql starts slowing down.. |
| > |
| > |
| |
| In the case of concurrent SELECTs and INSERT/UPDATE/DELETE operations |
| MySQL will slow down for sure. The more concurrent transactions you have |
| the worse MySQL will be. |
| |
| >>It also seems like the vacuum after each insert is unnecessary, unless |
| >>your also deleting/updating data behind it. Perhaps just running an |
| >>ANALYZE on the table would suffice while reducing overhead. |
| >> |
| >> |
| > |
| >I believe that was vacuum analyze only. But still it takes lot of time. Good |
| >thing is it's not blocking.. |
| > |
| >Anyway I don't think such frequent vacuums are going to convince planner to |
| >choose index scan over sequential scan. I am sure it's already convinced.. |
| > |
| > |
| |
| PostgreSQL allows you to improve execution plans by giving the planner a |
| hint. |
| In addition to that: if you need REAL performance and if you are running |
| similar queries consider using SPI. |
| |
| Also: 7.3 will support PREPARE/EXECUTE. |
| |
| If you are running MySQL you will not be able to add features to the |
| database easily. |
| In the case of PostgreSQL you have a broad range of simple interfaces |
| which make many things pretty simple (eg. optimized data types in < 50 |
| lines of C code). |
| |
| PostgreSQL is the database of the future and you can perform a lot of |
| tuning. |
| MySQL is a simple frontend to a filesystem and it is fast as long as you |
| are doing SELECT 1+1 operations. |
| |
| Also: Keep in mind that PostgreSQL has a wonderful core team. MySQL is |
| built on Monty Widenius and the core team = Monty. |
| Also: PostgreSQL = ANSI compilant, MySQL = Monty compliant |
| |
| In the past few years I have seen that there is no database system which |
| can beat PostgreSQL's flexibility and stability. |
| I am familiar with various database systems but believe: PostgreSQL is |
| the best choice. |
| |
| Hans |
| |
| |
| >Regards, |
| > Shridhar |
| > |
| >----------------------------------------------------------- |
| >Shridhar Daithankar |
| >LIMS CPE Team Member, PSPL. |
| >mailto:shridhar_daithankar@persistent.co.in |
| >Phone:- +91-20-5678900 Extn.270 |
| >Fax :- +91-20-5678901 |
| >----------------------------------------------------------- |
| > |
| > |
| >---------------------------(end of broadcast)--------------------------- |
| >TIP 6: Have you searched our list archives? |
| > |
| >http://archives.postgresql.org |
| > |
| > |
| |
| |
| |
| -- |
| *Cybertec Geschwinde u Schoenig* |
| Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria |
| Tel: +43/1/913 68 09; +43/664/233 90 75 |
| www.postgresql.at <http://www.postgresql.at>, cluster.postgresql.at |
| <http://cluster.postgresql.at>, www.cybertec.at |
| <http://www.cybertec.at>, kernel.cybertec.at <http://kernel.cybertec.at> |
| |
| |
| From pgsql-general-owner@postgresql.org Thu Oct 3 12:51:10 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <shridhar?daithankar@persistent.co.in>; 3 Oct 2002 16:51:12 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Subject: Re: [HACKERS] Large databases, performance |
| Date: Thu, 03 Oct 2002 18:53:32 +0200 |
| Message-ID: <latopug1vl51769nkn3rj2ltdhjvqrbfof@4ax.com> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <1033660649.21324.53.camel@camel> |
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| |
| On Thu, 03 Oct 2002 21:47:03 +0530, "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> wrote: |
| >I believe that was vacuum analyze only. |
| |
| Well there is |
| |
| VACUUM [tablename]; |
| |
| and there is |
| |
| ANALYZE [tablename]; |
| |
| And |
| |
| VACUUM ANALYZE [tablename]; |
| |
| is VACUUM followed by ANALYZE. |
| |
| Servus |
| Manfred |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 12:52:31 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id DEE8B4768CD |
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| From pgsql-performance-owner@postgresql.org Thu Oct 3 13:41:02 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 4F95847648F |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 13:40:59 -0400 (EDT) |
| Received: from lakemtao04.cox.net (lakemtao04.cox.net [68.1.17.241]) |
| by postgresql.org (Postfix) with ESMTP id 93BB0476482 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 13:40:58 -0400 (EDT) |
| Received: from localhost.localdomain ([68.11.66.83]) by lakemtao04.cox.net |
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| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 13:40:59 -0400 |
| Subject: Re: Large databases, performance |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <3D9CBAD7.23509.A908C61@localhost> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9CBAD7.23509.A908C61@localhost> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 03 Oct 2002 12:38:49 -0500 |
| Message-Id: <1033666730.28946.64.camel@haggis> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/14 |
| X-Sequence-Number: 31 |
| |
| On Thu, 2002-10-03 at 11:17, Shridhar Daithankar wrote: |
| > On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| > |
| [snip] |
| > > I'm curious, did you happen to run the select tests while also running |
| > > the insert tests? IIRC the older mysql versions have to lock the table |
| > > when doing the insert, so select performance goes in the dumper in that |
| > > scenario, perhaps that's not an issue with 3.23.52? |
| > |
| > IMO even if it locks tables that shouldn't affect select performance. It would |
| > be fun to watch when we insert multiple chunks of data and fire queries |
| > concurrently. I would be surprised if mysql starts slowing down.. |
| |
| What kind of lock? Shared lock or exclusive lock? If SELECT |
| performance tanked when doing simultaneous INSERTs, then maybe there |
| were exclusive table locks. |
| |
| -- |
| +------------------------------------------------------------+ |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "What other evidence do you have that they are terrorists, | |
| | other than that they trained in these camps?" | |
| | 17-Sep-2002 Katie Couric to an FBI agent regarding the 5 | |
| | men arrested near Buffalo NY | |
| +------------------------------------------------------------+ |
| |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 16:57:46 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 48CBB475AA1 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 16:57:44 -0400 (EDT) |
| Received: from lakemtao02.cox.net (lakemtao02.cox.net [68.1.17.243]) |
| by postgresql.org (Postfix) with ESMTP id A063C475A09 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 16:57:43 -0400 (EDT) |
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| id <20021003205743.MIEH12192.lakemtao02.cox.net@localhost.localdomain> |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 16:57:43 -0400 |
| Subject: Re: [HACKERS] Large databases, performance |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <3D9C7579.2010206@cybertec.at> |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9CBAD7.23509.A908C61@localhost> <3D9C7579.2010206@cybertec.at> |
| Content-Type: text/plain; charset=ISO-8859-1 |
| Content-Transfer-Encoding: quoted-printable |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 03 Oct 2002 15:55:35 -0500 |
| Message-Id: <1033678535.28946.158.camel@haggis> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/15 |
| X-Sequence-Number: 32 |
| |
| On Thu, 2002-10-03 at 11:51, Hans-J=FCrgen Sch=F6nig wrote: |
| > Shridhar Daithankar wrote: |
| >=20 |
| > >On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| [snip] |
| > PostgreSQL allows you to improve execution plans by giving the planner a= |
| =20 |
| > hint. |
| > In addition to that: if you need REAL performance and if you are running= |
| =20 |
| > similar queries consider using SPI. |
| |
| What is SPI? |
| |
| --=20 |
| +------------------------------------------------------------+ |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "What other evidence do you have that they are terrorists, | |
| | other than that they trained in these camps?" | |
| | 17-Sep-2002 Katie Couric to an FBI agent regarding the 5 | |
| | men arrested near Buffalo NY | |
| +------------------------------------------------------------+ |
| |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 17:09:21 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 9ED65476187 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 17:09:19 -0400 (EDT) |
| Received: from mail.libertyrms.com (unknown [209.167.124.227]) |
| by postgresql.org (Postfix) with ESMTP id C485647616D |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 17:09:18 -0400 (EDT) |
| Received: from andrew by mail.libertyrms.com with local (Exim 3.22 #3 |
| (Debian)) |
| id 17xDDk-0001Ue-00 |
| for <pgsql-performance@postgresql.org>; Thu, 03 Oct 2002 17:09:20 -0400 |
| Date: Thu, 3 Oct 2002 17:09:20 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: [HACKERS] Large databases, performance |
| Message-ID: <20021003170920.X18497@mail.libertyrms.com> |
| Reply-To: pgsql-performance@postgresql.org |
| Mail-Followup-To: pgsql-performance@postgresql.org |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9CBAD7.23509.A908C61@localhost> <3D9C7579.2010206@cybertec.at> |
| Mime-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
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| User-Agent: Mutt/1.2.5i |
| In-Reply-To: <3D9C7579.2010206@cybertec.at>; |
| from postgres@cybertec.at on Thu, Oct 03, 2002 at 06:51:05PM +0200 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/17 |
| X-Sequence-Number: 34 |
| |
| On Thu, Oct 03, 2002 at 06:51:05PM +0200, Hans-J?rgen Sch?nig wrote: |
| |
| > In the case of concurrent transactions MySQL does not do as well due to |
| > very bad locking behavious. PostgreSQL is far better because it does row |
| > level locking instead of table locking. |
| |
| It is my understanding that MySQL no longer does this on InnoDB |
| tables. Whether various bag-on-the-side table types are a good thing |
| I will leave to others; but there's no reason to go 'round making |
| claims about old versions of MySQL any more than there is a reason to |
| continue to talk about PostgreSQL not being crash safe. MySQL has |
| moved along nearly as quickly as PostgreSQL. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Thu Oct 3 17:02:38 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 98D55476265 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 17:02:36 -0400 (EDT) |
| Received: from beamish.nsd.ca (unknown [205.150.156.194]) |
| by postgresql.org (Postfix) with ESMTP id E0E64476264 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 3 Oct 2002 17:02:35 -0400 (EDT) |
| Received: (from smap@localhost) by beamish.nsd.ca (8.9.3/8.9.3) id RAA18011 |
| for <pgsql-performance@postgresql.org>; Thu, 3 Oct 2002 17:02:37 -0400 |
| X-Authentication-Warning: beamish.nsd.ca: smap set sender to <jllachan@nsd.ca> |
| using -f |
| Received: from reddog.nsd.ca(192.168.101.30) by beamish.nsd.ca via smap |
| (V2.1/2.1+anti-relay+anti-spam) |
| id xma018009; Thu, 3 Oct 02 17:02:31 -0400 |
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| by reddog.nsd.ca (8.8.7/8.8.7) with ESMTP id RAA22887 |
| for <pgsql-performance@postgresql.org>; Thu, 3 Oct 2002 17:02:13 -0400 |
| Message-ID: <3D9CB2A2.47A4F6F1@nsd.ca> |
| Date: Thu, 03 Oct 2002 17:12:02 -0400 |
| From: Jean-Luc Lachance <jllachan@nsd.ca> |
| X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.9-31 i686) |
| X-Accept-Language: en |
| MIME-Version: 1.0 |
| To: pgsql-performance@postgresql.org |
| Subject: use [PERF] instead of |
| References: <3D9C8712.9513.9C6521D@localhost> |
| <3D9CBAD7.23509.A908C61@localhost> <3D9C7579.2010206@cybertec.at> |
| <1033678535.28946.158.camel@haggis> |
| Content-Type: text/plain; charset=iso-8859-1 |
| Content-Transfer-Encoding: quoted-printable |
| X-MIME-Autoconverted: from 8bit to quoted-printable by reddog.nsd.ca id |
| RAA22887 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/16 |
| X-Sequence-Number: 33 |
| |
| May I suggest that instead of [pgsql-performance] that [PERF] be used to |
| save some of the subject line. |
| |
| Ron Johnson wrote: |
| >=20 |
| > On Thu, 2002-10-03 at 11:51, Hans-J=FCrgen Sch=F6nig wrote: |
| > > Shridhar Daithankar wrote: |
| > > |
| > > >On 3 Oct 2002 at 11:57, Robert Treat wrote: |
| > [snip] |
| > > PostgreSQL allows you to improve execution plans by giving the planner a |
| > > hint. |
| > > In addition to that: if you need REAL performance and if you are running |
| > > similar queries consider using SPI. |
| >=20 |
| > What is SPI? |
| >=20 |
| > -- |
| > +------------------------------------------------------------+ |
| > | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| > | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| > | | |
| > | "What other evidence do you have that they are terrorists, | |
| > | other than that they trained in these camps?" | |
| > | 17-Sep-2002 Katie Couric to an FBI agent regarding the 5 | |
| > | men arrested near Buffalo NY | |
| > +------------------------------------------------------------+ |
| >=20 |
| > ---------------------------(end of broadcast)--------------------------- |
| > TIP 2: you can get off all lists at once with the unregister command |
| > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) |
| |
| From pgsql-hackers-owner@postgresql.org Thu Oct 3 19:09:58 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 89E1D476450 |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 19:09:56 -0400 (EDT) |
| Received: from slammer.netnation.com (slammer.netnation.com [204.174.223.62]) |
| by postgresql.org (Postfix) with ESMTP id 540244762E0 |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 19:09:54 -0400 (EDT) |
| Received: from [10.10.10.11] (helo=mikeb.staff.netnation.com) |
| by slammer.netnation.com with esmtp (Exim 3.36 #1) |
| id 17xF6S-0004uw-00 |
| for pgsql-hackers@postgreSQL.org; Thu, 03 Oct 2002 16:09:56 -0700 |
| Subject: Re: [GENERAL] Performance while loading data and indexing |
| From: Mike Benoit <mikeb@netnation.com> |
| To: pgsql-hackers@postgreSQL.org |
| In-Reply-To: <m3ptv0ib90.fsf@varsoon.wireboard.com> |
| References: <200209262141.g8QLfMr09064@candle.pha.pa.us> |
| <m3ptv0ib90.fsf@varsoon.wireboard.com> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8-3mdk |
| Date: 03 Oct 2002 16:09:56 -0700 |
| Message-Id: <1033686597.31473.125.camel@mikeb.staff.netnation.com> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/178 |
| X-Sequence-Number: 29947 |
| |
| Some of you may be interested in this seemingly exhaustive benchmark |
| between ext2/3, ReiserFS, JFS, and XFS. |
| |
| http://www.osdl.org/presentations/lwe-jgfs.pdf |
| |
| |
| |
| From pgsql-hackers-owner@postgresql.org Thu Oct 3 19:35:53 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 06F03475AA1 |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 19:35:51 -0400 (EDT) |
| Received: from CopelandConsulting.Net (dsl-24293-ld.customer.centurytel.net |
| [209.142.135.135]) |
| by postgresql.org (Postfix) with ESMTP id 90432475F6A |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 19:35:40 -0400 (EDT) |
| Received: from mouse.copelandconsulting.net (mouse.copelandconsulting.net |
| [192.168.1.2]) |
| by CopelandConsulting.Net (8.10.1/8.10.1) with ESMTP id g93NZPd17537; |
| Thu, 3 Oct 2002 18:35:26 -0500 (CDT) |
| X-Trade-Id: <CCC.Thu, 3 Oct 2002 18:35:26 -0500 (CDT).Thu, |
| 3 Oct 2002 18:35:26 -0500 |
| (CDT).200210032335.g93NZPd17537.g93NZPd17537@CopelandConsulting.Net. |
| Subject: Re: [GENERAL] Performance while loading data and indexing |
| From: Greg Copeland <greg@CopelandConsulting.Net> |
| To: Mike Benoit <mikeb@netnation.com> |
| Cc: PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org> |
| In-Reply-To: <1033686597.31473.125.camel@mikeb.staff.netnation.com> |
| References: <200209262141.g8QLfMr09064@candle.pha.pa.us> |
| <m3ptv0ib90.fsf@varsoon.wireboard.com> |
| <1033686597.31473.125.camel@mikeb.staff.netnation.com> |
| Content-Type: multipart/signed; micalg=pgp-sha1; |
| protocol="application/pgp-signature"; |
| boundary="=-BuYK0VVffYM+zNI+A4b0" |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 03 Oct 2002 18:35:34 -0500 |
| Message-Id: <1033688135.13005.28.camel@mouse.copelandconsulting.net> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/180 |
| X-Sequence-Number: 29949 |
| |
| --=-BuYK0VVffYM+zNI+A4b0 |
| Content-Type: text/plain |
| Content-Transfer-Encoding: quoted-printable |
| |
| Hey, excellent. Thanks! |
| |
| Based on that, it appears that XFS is a pretty good FS to use. For me, |
| the real surprise was how well reiserfs performed. |
| |
| Greg |
| |
| On Thu, 2002-10-03 at 18:09, Mike Benoit wrote: |
| > Some of you may be interested in this seemingly exhaustive benchmark |
| > between ext2/3, ReiserFS, JFS, and XFS. |
| >=20 |
| > http://www.osdl.org/presentations/lwe-jgfs.pdf |
| >=20 |
| >=20 |
| >=20 |
| > ---------------------------(end of broadcast)--------------------------- |
| > TIP 6: Have you searched our list archives? |
| >=20 |
| > http://archives.postgresql.org |
| |
| |
| --=-BuYK0VVffYM+zNI+A4b0 |
| Content-Type: application/pgp-signature; name=signature.asc |
| Content-Description: This is a digitally signed message part |
| |
| -----BEGIN PGP SIGNATURE----- |
| Version: GnuPG v1.2.0 (GNU/Linux) |
| |
| iD8DBQA9nNRG4lr1bpbcL6kRAjiYAJsFu0Zzy9SypyS71KkTsIUCu93D+wCfV7Sl |
| pDPuo2tpeJBVZJzbcnN9WDs= |
| =IsJZ |
| -----END PGP SIGNATURE----- |
| |
| --=-BuYK0VVffYM+zNI+A4b0-- |
| |
| |
| From pgsql-hackers-owner@postgresql.org Thu Oct 3 20:01:32 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 175E947600E |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 20:01:31 -0400 (EDT) |
| Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) |
| by postgresql.org (Postfix) with ESMTP id B5F71475B84 |
| for <pgsql-hackers@postgresql.org>; |
| Thu, 3 Oct 2002 20:01:18 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g93NxuZ07976; |
| Thu, 3 Oct 2002 19:59:56 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210032359.g93NxuZ07976@candle.pha.pa.us> |
| Subject: Re: [GENERAL] Performance while loading data and indexing |
| In-Reply-To: <1033688135.13005.28.camel@mouse.copelandconsulting.net> |
| To: Greg Copeland <greg@CopelandConsulting.Net> |
| Date: Thu, 3 Oct 2002 19:59:56 -0400 (EDT) |
| Cc: Mike Benoit <mikeb@netnation.com>, |
| PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org> |
| X-Mailer: ELM [version 2.4ME+ PL99 (25)] |
| MIME-Version: 1.0 |
| Content-Transfer-Encoding: 7bit |
| Content-Type: text/plain; charset=US-ASCII |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/184 |
| X-Sequence-Number: 29953 |
| |
| Greg Copeland wrote: |
| -- Start of PGP signed section. |
| > Hey, excellent. Thanks! |
| > |
| > Based on that, it appears that XFS is a pretty good FS to use. For me, |
| > the real surprise was how well reiserfs performed. |
| > |
| |
| OK, hardware performance paper updated: |
| |
| --------------------------------------------------------------------------- |
| |
| File system choice is particularly difficult on Linux because there are |
| so many file system choices, and none of them are optimal: ext2 is not |
| entirely crash-safe, ext3, xfs, and jfs are journal-based, and Reiser is |
| optimized for small files and does journalling. The journalling file |
| systems can be significantly slower than ext2 but when crash recovery is |
| required, ext2 isn't an option. If ext2 must be used, mount it with sync |
| enabled. Some people recommend xfs or an ext3 filesystem mounted with |
| data=writeback. |
| |
| -- |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
| |
| From pgsql-general-owner@postgresql.org Fri Oct 4 04:00:33 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 88451476148 |
| for <pgsql-general@postgresql.org>; |
| Fri, 4 Oct 2002 04:00:26 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id D1A59476082 |
| for <pgsql-general@postgresql.org>; |
| Fri, 4 Oct 2002 04:00:24 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g9481rO29203 |
| for <pgsql-general@postgresql.org>; Fri, 4 Oct 2002 13:31:53 +0530 |
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| Fri, 4 Oct 2002 13:31:53 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| "pankaj M. Tolani" <pankaj@pspl.co.in> |
| Date: Fri, 04 Oct 2002 13:30:54 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [HACKERS] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
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| |
| On 3 Oct 2002 at 18:53, Manfred Koizar wrote: |
| |
| > On Thu, 03 Oct 2002 21:47:03 +0530, "Shridhar Daithankar" |
| > <shridhar_daithankar@persistent.co.in> wrote: |
| > >I believe that was vacuum analyze only. |
| > |
| > Well there is |
| > |
| > VACUUM [tablename]; |
| > |
| > and there is |
| > |
| > ANALYZE [tablename]; |
| > |
| > And |
| > |
| > VACUUM ANALYZE [tablename]; |
| > |
| > is VACUUM followed by ANALYZE. |
| |
| I was using vacuum analyze. |
| |
| Good that you pointed out. Now I will modify the postgresql auto vacuum daemon |
| that I wrote to analyze only in case of excesive inserts. I hope that's lighter |
| on performance compared to vacuum analyze.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| Mix's Law: There is nothing more permanent than a temporary building. There is |
| nothing more permanent than a temporary tax. |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 12:04:21 2002 |
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| with HTTP id 1771475; Fri, 04 Oct 2002 08:54:56 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Comparitive UPDATE speed |
| To: Ron Johnson <ron.l.johnson@cox.net> |
| Cc: pgsql-performance@postgresql.org |
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| |
| Folks, |
| |
| Sorry for the double-quoting here. I sent this to just Ron by |
| accident. My original question is double-quoted, Ron is quoted, and my |
| responses are below. Thanks! |
| |
| > > Ok, I'm still confused. |
| > > |
| > > I'm updating a (not not indexed) field in a 117,000 row table based |
| > on |
| > > information in another 117,000 row table. The update is an |
| > integer, and the |
| > > linking fields are indexed. Yet the two queries are flattening my |
| > |
| > > dual-processor, RAID5 database server for up to 11 minutes ... |
| > using 230mb |
| > > ram the entire time. I simply can't believe that these two |
| > queries are that |
| > > difficult. |
| > |
| > So there's no index on elbs_matter_links.case_id? From your original |
| > |
| > post, I thought that there *is* an index on that field. |
| |
| I'm now dropping it before the update. Unfortunately, dropping the |
| index made no appreciable gain in performance. |
| |
| > > I've increased the memory available to the update to 256mb, and |
| > tried forcing |
| > > an index scan ... to no avail. Ideas, please? |
| > > |
| > > The queries: |
| > > |
| > > UPDATE elbs_matter_links SET case_id = case_clients.case_id |
| > > FROM case_clients |
| > > WHERE elbs_matter_links.mmatter = case_clients.matter_no; |
| > |
| > What happens if you run the query: |
| > SELECT eml.case_id, cc.case_id, eml.mmatter, cc.matter_no |
| > FROM elbs_matter_links eml, |
| > case_clients cc |
| > WHERE eml.mmatter = cc.matter_no; |
| > |
| > That, for all intents and purposes, is your UPDATE statement, just |
| > without doing the UPDATE. How fast does it run? |
| |
| Slowly. It takes about 60 seconds to return data. This may be the |
| problem. Thoughts? Here's EXPLAIN output: |
| |
| Hash Join (cost=3076.10..91842.88 rows=108648 width=40) |
| -> Seq Scan on elbs_matter_links eml (cost=0.00..85641.87 |
| rows=117787 width=20) |
| -> Hash (cost=2804.48..2804.48 rows=108648 width=20) |
| -> Seq Scan on case_clients cc (cost=0.00..2804.48 |
| rows=108648 width=20) |
| |
| According to the parser, using the indexes would be worse: |
| |
| Merge Join (cost=0.00..520624.38 rows=108648 width=40) |
| -> Index Scan using idx_eml_mmatter on elbs_matter_links eml |
| (cost=0.00..451735.00 rows=117787 width=20) |
| -> Index Scan using idx_caseclients_matter on case_clients cc |
| (cost=0.00..66965.20 rows=108648 width=20) |
| |
| Though in practice, a forced index scan returns rows in about 60 |
| seconds, same as the SeqScan version. |
| |
| All of this seems very costly for a query that, while it does return a |
| lot of rows, is essentially a very simple query. |
| |
| More importantly, on the hardware I'm using, I would expect better |
| performance that I get on my laptop ... and I'm not seeing it. I just |
| can't believe that the simple query above could soak 200mb of RAM for a |
| full 60 seconds to return a result. It's like queries over a certain |
| result size on the system choke postgres. |
| |
| |
| My reference data below: |
| ============================================== |
| |
| > |
| > > UPDATE elbs_matter_links SET case_id = cases.case_id |
| > > FROM cases |
| > > WHERE elbs_matter_links.docket = cases.docket |
| > > AND elbs_matter_links.case_id IS NULL; |
| > > |
| > > |
| > > EXPLAIN output: |
| > > |
| > > Hash Join (cost=4204.83..39106.77 rows=8473 width=299) |
| > > -> Index Scan using idx_eml_mmatter on elbs_matter_links |
| > > (cost=0.00..34668.94 rows=8473 width=279) |
| > > -> Hash (cost=2808.38..2808.38 rows=109038 width=20) |
| > > -> Seq Scan on case_clients (cost=0.00..2808.38 |
| > rows=109038 |
| > > width=20) |
| > > |
| > > Nested Loop (cost=0.00..32338.47 rows=99 width=300) |
| > > -> Seq Scan on cases (cost=0.00..9461.97 rows=4297 width=21) |
| > > -> Index Scan using idx_eml_docket on elbs_matter_links |
| > (cost=0.00..5.31 |
| > > rows=1 width=279) |
| > > |
| > > Table defintions: |
| > > |
| > > Table "elbs_matter_links" |
| > > Column | Type | Modifiers |
| > > ------------------+-----------------------+----------------------- |
| > > mmatter | character varying(15) | not null |
| > > case_id | integer | |
| > > matter_check | character varying(20) | not null default 'OK' |
| > > docket | character varying(50) | |
| > > case_name | character varying(50) | |
| > > practice | character varying(50) | |
| > > opp_counsel_name | character varying(50) | |
| > > opp_counsel_id | integer | |
| > > act_type | character varying(10) | |
| > > lead_case_id | integer | |
| > > lead_case_docket | character varying(50) | |
| > > disease | character varying(50) | |
| > > docket_no | character varying(25) | |
| > > juris_state | character varying(6) | |
| > > juris_local | character varying(20) | |
| > > status | smallint | not null default 1 |
| > > client_id | integer | |
| > > office_loc | character varying(5) | |
| > > date_filed | date | |
| > > date_served | date | |
| > > date_resolved | date | |
| > > case_status | character varying(5) | |
| > > settle_amount | numeric(12,2) | default 0 |
| > > narrative | text | |
| > > comment | character varying(50) | |
| > > client_no | character varying(10) | |
| > > juris_id | integer | |
| > > Indexes: idx_eml_check, |
| > > idx_eml_docket, |
| > > idx_eml_mmatter |
| > > Primary key: elbs_matter_links_pkey |
| > > |
| > > Table "case_clients" |
| > > Column | Type | |
| > Modifiers |
| > > |
| > |
| ------------------+-----------------------+---------------------------------------------------- |
| > > case_client_id | integer | not null default |
| > > nextval('case_clients_seq'::text) |
| > > case_id | integer | not null |
| > > client_id | integer | not null |
| > > office_loc | character varying(5) | |
| > > date_filed | date | |
| > > date_served | date | |
| > > date_resolved | date | |
| > > matter_no | character varying(15) | not null |
| > > case_status | character varying(5) | not null |
| > > settle_amount | numeric(14,2) | not null default 0 |
| > > matter_narrative | text | |
| > > comment | character varying(50) | |
| > > Indexes: idx_case_clients_client, |
| > > idx_caseclients_case, |
| > > idx_caseclients_matter, |
| > > idx_caseclients_resolved, |
| > > idx_caseclients_served, |
| > > idx_caseclients_status |
| > > Primary key: case_clients_pkey |
| > > |
| > > |
| > > Table "cases" |
| > > Column | Type | |
| > Modifiers |
| > > |
| > |
| ------------------+-----------------------+--------------------------------------------- |
| > > case_id | integer | not null default |
| > > nextval('cases_seq'::text) |
| > > docket | character varying(50) | not null |
| > > case_name | character varying(50) | not null |
| > > practice | character varying(50) | not null |
| > > opp_counsel_name | character varying(50) | |
| > > opp_counsel_id | integer | |
| > > act_type | character varying(10) | |
| > > lead_case_id | integer | |
| > > lead_case_docket | character varying(50) | |
| > > disease | character varying(50) | |
| > > docket_no | character varying(25) | not null |
| > > juris_state | character varying(6) | not null |
| > > juris_local | character varying(20) | |
| > > tgroup_id | integer | |
| > > status | smallint | not null default 1 |
| > > juris_id | integer | |
| > > Indexes: idx_case_cases_juris, |
| > > idx_cases_docket, |
| > > idx_cases_lead, |
| > > idx_cases_name, |
| > > idx_cases_status, |
| > > idx_cases_tgroup, |
| > > idx_lower_case_name |
| > > |
| > > |
| > > |
| > > -- |
| > > Josh Berkus |
| > > josh@agliodbs.com |
| > > Aglio Database Solutions |
| > > San Francisco |
| > -- |
| > +------------------------------------------------------------+ |
| > | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| > | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| > | | |
| > | "What other evidence do you have that they are terrorists, | |
| > | other than that they trained in these camps?" | |
| > | 17-Sep-2002 Katie Couric to an FBI agent regarding the 5 | |
| > | men arrested near Buffalo NY | |
| > +------------------------------------------------------------+ |
| > |
| |
| ______AGLIO DATABASE SOLUTIONS___________________________ |
| Josh Berkus |
| Complete information technology josh@agliodbs.com |
| and data management solutions (415) 565-7293 |
| for law firms, small businesses fax 621-2533 |
| and non-profit organizations. San Francisco |
| |
| From pgsql-general-owner@postgresql.org Fri Oct 4 12:17:40 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Fri, 4 Oct 2002 10:13:00 -0600 (MDT) |
| Date: Fri, 4 Oct 2002 10:05:10 -0600 (MDT) |
| From: "scott.marlowe" <scott.marlowe@ihs.com> |
| To: <hs@cybertec.at> |
| Cc: <shridhar_daithankar@persistent.co.in>, |
| <pgsql-performance@postgresql.org>, <pgsql-general@postgresql.org> |
| Subject: Re: [HACKERS] Large databases, performance |
| In-Reply-To: <3D9C7579.2010206@cybertec.at> |
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| |
| On Thu, 3 Oct 2002, Hans-J�rgen Sch�nig wrote: |
| |
| > In the case of concurrent transactions MySQL does not do as well due to |
| > very bad locking behavious. PostgreSQL is far better because it does row |
| > level locking instead of table locking. |
| > If you have many concurrent transactions MySQL performs some sort of |
| > "self-denial-of-service". I'd choose PostgreSQL in order to make sure |
| > that the database does not block. |
| |
| While I'm no big fan of MySQL, I must point out that with innodb tables, |
| the locking is row level, and the ability to handle parallel read / write |
| is much improved. |
| |
| Also, Postgresql does NOT use row level locking, it uses MVCC, which is |
| "better than row level locking" as Tom puts it. |
| |
| Of course, hot backup is only 2,000 Euros for an innodb table mysql, while |
| hot backup for postgresql is free. :-) |
| |
| That said, MySQL still doesn't handle parallel load nearly as well as |
| postgresql, it's just better than it once was. |
| |
| > Also: Keep in mind that PostgreSQL has a wonderful core team. MySQL is |
| > built on Monty Widenius and the core team = Monty. |
| > Also: PostgreSQL = ANSI compilant, MySQL = Monty compliant |
| |
| This is a very valid point. The "committee" that creates and steers |
| Postgresql is very much a meritocracy. The "committee" that steers MySQL |
| is Monty. |
| |
| I'm much happier knowing that every time something important needs to be |
| done we have a whole cupboard full of curmudgeons arguing the fine points |
| so that the "right thing" gets done. |
| |
| |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 08:37:33 2002 |
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| To: "scott.marlowe" <scott.marlowe@ihs.com>, |
| pgsql-general@postgresql.org |
| Subject: Re: [HACKERS] Large databases, performance |
| References: <Pine.LNX.4.33.0210040958440.9386-100000@css120.ihs.com> |
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| |
| MVCC = great ... |
| I know that is not row level locking but that's the way things can be |
| explained more easily. Many people are asking my how things work and |
| this way it is easier to understand. Never tell a trainee about deadlock |
| detection and co *g*. |
| |
| I am happy that the PostgreSQL core team + all developers are not like |
| Monty ... |
| I am happy to PostgreSQL has developers such as Bruce, Tom, Jan, Marc, |
| Vadim, Joe, Neil, Christopher, etc. (just to name a few) ... |
| |
| Yes, it is said to be better than it was but that's not the point: |
| MySQL = Monty SQL <> ANSI SQL ... |
| |
| Believe me, the table will turn and finally the better system will succeed. |
| One we have clustering, PITR, etc. running people will see how real |
| databases work :). |
| |
| Hans |
| |
| |
| |
| scott.marlowe wrote: |
| |
| >On Thu, 3 Oct 2002, Hans-J�rgen Sch�nig wrote: |
| > |
| > |
| > |
| >>In the case of concurrent transactions MySQL does not do as well due to |
| >>very bad locking behavious. PostgreSQL is far better because it does row |
| >>level locking instead of table locking. |
| >>If you have many concurrent transactions MySQL performs some sort of |
| >>"self-denial-of-service". I'd choose PostgreSQL in order to make sure |
| >>that the database does not block. |
| >> |
| >> |
| > |
| >While I'm no big fan of MySQL, I must point out that with innodb tables, |
| >the locking is row level, and the ability to handle parallel read / write |
| >is much improved. |
| > |
| >Also, Postgresql does NOT use row level locking, it uses MVCC, which is |
| >"better than row level locking" as Tom puts it. |
| > |
| >Of course, hot backup is only 2,000 Euros for an innodb table mysql, while |
| >hot backup for postgresql is free. :-) |
| > |
| >That said, MySQL still doesn't handle parallel load nearly as well as |
| >postgresql, it's just better than it once was. |
| > |
| > |
| > |
| >>Also: Keep in mind that PostgreSQL has a wonderful core team. MySQL is |
| >>built on Monty Widenius and the core team = Monty. |
| >>Also: PostgreSQL = ANSI compilant, MySQL = Monty compliant |
| >> |
| >> |
| > |
| >This is a very valid point. The "committee" that creates and steers |
| >Postgresql is very much a meritocracy. The "committee" that steers MySQL |
| >is Monty. |
| > |
| >I'm much happier knowing that every time something important needs to be |
| >done we have a whole cupboard full of curmudgeons arguing the fine points |
| >so that the "right thing" gets done. |
| > |
| > |
| |
| -- |
| *Cybertec Geschwinde u Schoenig* |
| Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria |
| Tel: +43/1/913 68 09; +43/664/233 90 75 |
| www.postgresql.at <http://www.postgresql.at>, cluster.postgresql.at |
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| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 12:36:02 2002 |
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| <20021003170920.X18497@mail.libertyrms.com> |
| Subject: Re: Large databases, performance |
| Date: Fri, 4 Oct 2002 18:38:21 +0200 |
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| |
| Andrew Sullivan <andrew@libertyrms.info> wrote: |
| |
| > On Thu, Oct 03, 2002 at 06:51:05PM +0200, Hans-J?rgen Sch?nig wrote: |
| > |
| > > In the case of concurrent transactions MySQL does not do as well due to |
| > > very bad locking behavious. PostgreSQL is far better because it does row |
| > > level locking instead of table locking. |
| > |
| > It is my understanding that MySQL no longer does this on InnoDB |
| > tables. Whether various bag-on-the-side table types are a good thing |
| > I will leave to others; but there's no reason to go 'round making |
| > claims about old versions of MySQL any more than there is a reason to |
| > continue to talk about PostgreSQL not being crash safe. MySQL has |
| > moved along nearly as quickly as PostgreSQL. |
| |
| Locking and transactions is not fine in MySQL (with InnoDB) though. I tried |
| to do selects on a table I was concurrently inserting to. In a single thread |
| I was constantly inserting 1000 rows per transaction. While inserting I did |
| some random selects on the same table. It often happend that the insert |
| transactions were aborted due to dead lock problems. There I see the problem |
| with locking reads. |
| I like PostgreSQL's MVCC! |
| |
| Regards, |
| Michael Paesold |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 12:44:01 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-performance@postgresql.org>; Fri, 04 Oct 2002 12:44:03 -0400 |
| Date: Fri, 4 Oct 2002 12:44:03 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| Message-ID: <20021004124403.I949@mail.libertyrms.com> |
| Mail-Followup-To: pgsql-performance@postgresql.org |
| References: <1033708425.28946.203.camel@haggis> |
| <web-1771475@davinci.ethosmedia.com> |
| Mime-Version: 1.0 |
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| from josh@agliodbs.com on Fri, Oct 04, 2002 at 08:54:56AM -0700 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/22 |
| X-Sequence-Number: 39 |
| |
| On Fri, Oct 04, 2002 at 08:54:56AM -0700, Josh Berkus wrote: |
| |
| > Slowly. It takes about 60 seconds to return data. This may be the |
| > problem. Thoughts? Here's EXPLAIN output: |
| |
| [. . .] |
| |
| > According to the parser, using the indexes would be worse: |
| |
| Have you run this with EXPLAIN ANALYSE? It will actually perform the |
| necessary steps, so it will reveal if the planner is getting |
| something wrong. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-general-owner@postgresql.org Fri Oct 4 12:47:40 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Fri, 4 Oct 2002 12:47:39 -0400 (EDT) |
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| Fri, 04 Oct 2002 09:46:13 -0600 |
| From: "David Blood" <david@matraex.com> |
| To: <pgsql-general@postgresql.org> |
| Subject: Pinning a table into memory |
| Date: Fri, 4 Oct 2002 10:46:57 -0600 |
| Message-ID: <03a301c26bc5$a799a970$1f00a8c0@redwood> |
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| |
| |
| In Oracle you can Pin large objects into memory to prevent frequent |
| reloads. Is there anyway to do this with Postgres? It appears that some |
| of our tables that get hit a lot may get kicked out of memory when we |
| access some of our huge tables. Then they have to wait for I/O to get |
| loaded back in. |
| |
| |
| David Blood |
| Matraex, Inc |
| |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 14:14:35 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 5CDC647627D |
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| Fri, 4 Oct 2002 14:14:33 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id 8C29147620C |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 14:14:32 -0400 (EDT) |
| Received: from [216.135.165.74] (HELO lazarus) |
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| with ESMTP-TLS id 1771672; Fri, 04 Oct 2002 11:12:28 -0700 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| Date: Fri, 4 Oct 2002 11:13:09 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <1033708425.28946.203.camel@haggis> |
| <web-1771475@davinci.ethosmedia.com> |
| <20021004124403.I949@mail.libertyrms.com> |
| In-Reply-To: <20021004124403.I949@mail.libertyrms.com> |
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| X-Archive-Number: 200210/23 |
| X-Sequence-Number: 40 |
| |
| |
| Andrew, |
| |
| > Have you run this with EXPLAIN ANALYSE? It will actually perform the |
| > necessary steps, so it will reveal if the planner is getting |
| > something wrong. |
| |
| Here it is: |
| |
| Hash Join (cost=3D3076.10..91842.88 rows=3D108648 width=3D40) (actual=20 |
| time=3D18625.19..22823.39 rows=3D108546 loops=3D1) |
| -> Seq Scan on elbs_matter_links eml (cost=3D0.00..85641.87 rows=3D1177= |
| 87=20 |
| width=3D20) (actual time=3D18007.69..19515.63 rows=3D117787 loops=3D1) |
| -> Hash (cost=3D2804.48..2804.48 rows=3D108648 width=3D20) (actual=20 |
| time=3D602.12..602.12 rows=3D0 loops=3D1) |
| -> Seq Scan on case_clients cc (cost=3D0.00..2804.48 rows=3D10864= |
| 8=20 |
| width=3D20) (actual time=3D5.18..370.68 rows=3D108648 loops=3D1) |
| Total runtime: 22879.26 msec |
| |
| The above doesn't seem bad, except that this is some serious hardware in th= |
| is=20 |
| system and 23 seconds right after VACUUM ANALYZE is too long. I've a feeli= |
| ng=20 |
| that I botched one of my postgresql.conf parameters or something. |
| |
| I'll do an explain for the UPDATE query later, when the users are off the= |
| =20 |
| system. |
| |
| -Josh Berkus |
| |
| --=20 |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 14:25:29 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id F25084766A2 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 14:25:27 -0400 (EDT) |
| Received: from mail.libertyrms.com (unknown [209.167.124.227]) |
| by postgresql.org (Postfix) with ESMTP id 1CD304762E0 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 14:25:24 -0400 (EDT) |
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| (Debian)) |
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| for <pgsql-performance@postgresql.org>; Fri, 04 Oct 2002 14:25:23 -0400 |
| Date: Fri, 4 Oct 2002 14:25:23 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| Message-ID: <20021004142523.M949@mail.libertyrms.com> |
| Mail-Followup-To: pgsql-performance@postgresql.org |
| References: <1033708425.28946.203.camel@haggis> |
| <web-1771475@davinci.ethosmedia.com> |
| <20021004124403.I949@mail.libertyrms.com> |
| <200210041113.10008.josh@agliodbs.com> |
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| In-Reply-To: <200210041113.10008.josh@agliodbs.com>; |
| from josh@agliodbs.com on Fri, Oct 04, 2002 at 11:13:09AM -0700 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/24 |
| X-Sequence-Number: 41 |
| |
| On Fri, Oct 04, 2002 at 11:13:09AM -0700, Josh Berkus wrote: |
| > |
| > Andrew, |
| > |
| > > Have you run this with EXPLAIN ANALYSE? It will actually perform the |
| > > necessary steps, so it will reveal if the planner is getting |
| > > something wrong. |
| > |
| > Here it is: |
| |
| Oops, sorry. What if you force the index use here? Just because the |
| planner thinks that's more expensive doesn't mean that it is. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-general-owner@postgresql.org Fri Oct 4 14:47:50 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id D51644762E0 |
| for <pgsql-general@postgresql.org>; |
| Fri, 4 Oct 2002 14:47:49 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 1D4394762E2 |
| for <pgsql-general@postgresql.org>; |
| Fri, 4 Oct 2002 14:47:49 -0400 (EDT) |
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| Fri, 4 Oct 2002 14:47:48 -0400 (EDT) |
| To: "David Blood" <david@matraex.com> |
| Cc: pgsql-general@postgresql.org |
| Subject: Re: Pinning a table into memory |
| In-reply-to: <03a301c26bc5$a799a970$1f00a8c0@redwood> |
| References: <03a301c26bc5$a799a970$1f00a8c0@redwood> |
| Comments: In-reply-to "David Blood" <david@matraex.com> |
| message dated "Fri, 04 Oct 2002 10:46:57 -0600" |
| Date: Fri, 04 Oct 2002 14:47:47 -0400 |
| Message-ID: <25545.1033757267@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/274 |
| X-Sequence-Number: 31272 |
| |
| "David Blood" <david@matraex.com> writes: |
| > In Oracle you can Pin large objects into memory to prevent frequent |
| > reloads. Is there anyway to do this with Postgres? |
| |
| I can never understand why people think this would be a good idea. |
| If you're hitting a table frequently, it will stay in memory anyway |
| (either in Postgres shared buffers or kernel disk cache). If you're |
| not hitting it frequently enough to keep it swapped in, then whatever |
| is getting swapped in instead is probably a better candidate to be |
| occupying the space. ISTM that a manual "pin this table" knob would |
| mostly have the effect of making performance worse, whenever the |
| system activity is slightly different from the situation you had in |
| mind when you installed the pin. |
| |
| Having said that, I'll freely concede that our cache management |
| algorithms could use improvement (and there are people looking at |
| that right now). But a manual pin doesn't seem like a better answer. |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 15:10:49 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 4835B47610A |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:10:48 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id A5D4B4760DB |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:10:47 -0400 (EDT) |
| Received: from [216.135.165.74] (HELO lazarus) |
| by davinci.ethosmedia.com (CommuniGate Pro SMTP 3.5.9) |
| with ESMTP-TLS id 1771773; Fri, 04 Oct 2002 12:09:01 -0700 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| Date: Fri, 4 Oct 2002 12:09:42 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <1033708425.28946.203.camel@haggis> |
| <200210041113.10008.josh@agliodbs.com> |
| <20021004142523.M949@mail.libertyrms.com> |
| In-Reply-To: <20021004142523.M949@mail.libertyrms.com> |
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| X-Archive-Number: 200210/25 |
| X-Sequence-Number: 42 |
| |
| |
| Andrew, |
| |
| > Oops, sorry. What if you force the index use here? Just because the |
| > planner thinks that's more expensive doesn't mean that it is. |
| |
| Yeah, I tried it ... no faster, no slower, really. |
| |
| BTW, in case you missed it, the real concern is that an UPDATE query simila= |
| r=20 |
| to the SELECT query we are discussing takes over 10 minutes, which on this= |
| =20 |
| hardware is ridiculous. Robert suggested that we test the SELECT query to= |
| =20 |
| see if there were general performance problems; apparently, there are. |
| |
| The hardware I'm using is: |
| dual-processor Athalon 1400mhz motherboard |
| raid 5 UW SCSI drive array with 3 drives |
| 512mb DDR RAM |
| SuSE Linux 7.3 (Kernel 2.4.10) |
| Postgres is on its own LVM partition |
| PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC 2.95.3 |
| (will upgrade to 7.2.3 very soon) |
| Postgresql.conf has: fdatasync, various chared memory tuned to allocate 256= |
| mb=20 |
| to postgres (which seems to be working correctly). |
| Debug level 2. |
| |
| When the UPDATE query takes a long time, I generally can watch the log hove= |
| r=20 |
| in the land of "Reaping dead child processes" for 30-90 seconds per=20 |
| iteration. |
| |
| --=20 |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 15:24:16 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 90A1D475BA1 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:24:15 -0400 (EDT) |
| Received: from mail.libertyrms.com (unknown [209.167.124.227]) |
| by postgresql.org (Postfix) with ESMTP id D62FC47580B |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:24:14 -0400 (EDT) |
| Received: from andrew by mail.libertyrms.com with local (Exim 3.22 #3 |
| (Debian)) |
| id 17xY3b-0006bh-00 |
| for <pgsql-performance@postgresql.org>; Fri, 04 Oct 2002 15:24:15 -0400 |
| Date: Fri, 4 Oct 2002 15:24:15 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| Message-ID: <20021004152415.T949@mail.libertyrms.com> |
| Mail-Followup-To: pgsql-performance@postgresql.org |
| References: <1033708425.28946.203.camel@haggis> |
| <200210041113.10008.josh@agliodbs.com> |
| <20021004142523.M949@mail.libertyrms.com> |
| <200210041209.42665.josh@agliodbs.com> |
| Mime-Version: 1.0 |
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| User-Agent: Mutt/1.2.5i |
| In-Reply-To: <200210041209.42665.josh@agliodbs.com>; |
| from josh@agliodbs.com on Fri, Oct 04, 2002 at 12:09:42PM -0700 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/26 |
| X-Sequence-Number: 43 |
| |
| On Fri, Oct 04, 2002 at 12:09:42PM -0700, Josh Berkus wrote: |
| |
| > BTW, in case you missed it, the real concern is that an UPDATE query similar |
| > to the SELECT query we are discussing takes over 10 minutes, which on this |
| > hardware is ridiculous. Robert suggested that we test the SELECT query to |
| > see if there were general performance problems; apparently, there are. |
| |
| Yes, that's my thought, too. |
| |
| > Postgresql.conf has: fdatasync, various chared memory tuned to allocate 256mb |
| > to postgres (which seems to be working correctly). |
| |
| Hmm. Are you swapping? Lots of temp files? (I presume you've been |
| over all that.) Half your physical memory seems pretty dangerous to |
| me. If oyu reduce that, does it help? |
| |
| > When the UPDATE query takes a long time, I generally can watch the log hover |
| > in the land of "Reaping dead child processes" for 30-90 seconds per |
| > iteration. |
| |
| Ick. Hmm. What sort of numbers do you get from vmstat, iostat, sar, |
| and friends? |
| |
| A |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 15:41:17 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id AB43E476094 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:41:15 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 11B5E475EE2 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:41:15 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g94JfEhR026114; |
| Fri, 4 Oct 2002 15:41:14 -0400 (EDT) |
| To: Josh Berkus <josh@agliodbs.com> |
| Cc: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| In-reply-to: <200210041113.10008.josh@agliodbs.com> |
| References: <1033708425.28946.203.camel@haggis> |
| <web-1771475@davinci.ethosmedia.com> |
| <20021004124403.I949@mail.libertyrms.com> |
| <200210041113.10008.josh@agliodbs.com> |
| Comments: In-reply-to Josh Berkus <josh@agliodbs.com> |
| message dated "Fri, 04 Oct 2002 11:13:09 -0700" |
| Date: Fri, 04 Oct 2002 15:41:14 -0400 |
| Message-ID: <26113.1033760474@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/27 |
| X-Sequence-Number: 44 |
| |
| Josh Berkus <josh@agliodbs.com> writes: |
| > Hash Join (cost=3076.10..91842.88 rows=108648 width=40) (actual |
| > time=18625.19..22823.39 rows=108546 loops=1) |
| > -> Seq Scan on elbs_matter_links eml (cost=0.00..85641.87 rows=117787 |
| > width=20) (actual time=18007.69..19515.63 rows=117787 loops=1) |
| > -> Hash (cost=2804.48..2804.48 rows=108648 width=20) (actual |
| > time=602.12..602.12 rows=0 loops=1) |
| > -> Seq Scan on case_clients cc (cost=0.00..2804.48 rows=108648 |
| > width=20) (actual time=5.18..370.68 rows=108648 loops=1) |
| > Total runtime: 22879.26 msec |
| |
| Hm. Why does it take 19500 milliseconds to read 117787 rows from |
| elbs_matter_links, if 108648 rows can be read from case_clients in 370 |
| msec? And why does the output show that the very first of those rows |
| was returned only after 18000 msec? |
| |
| I am suspicious that this table has a huge number of empty pages in it, |
| mostly at the beginning. If so, a VACUUM FULL would help. (Try |
| "vacuum full verbose elbs_matter_links" and see if it indicates it's |
| reclaiming any large number of pages.) |
| |
| If that proves to be the answer, you need to look to your FSM |
| parameters, and perhaps arrange for more frequent regular vacuums |
| of this table. |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 15:45:35 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id A87F1476D3E |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:45:34 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id D4F64476BFA |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 15:45:32 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g94JjShR026160; |
| Fri, 4 Oct 2002 15:45:28 -0400 (EDT) |
| To: Josh Berkus <josh@agliodbs.com> |
| Cc: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Comparitive UPDATE speed |
| In-reply-to: <200210041209.42665.josh@agliodbs.com> |
| References: <1033708425.28946.203.camel@haggis> |
| <200210041113.10008.josh@agliodbs.com> |
| <20021004142523.M949@mail.libertyrms.com> |
| <200210041209.42665.josh@agliodbs.com> |
| Comments: In-reply-to Josh Berkus <josh@agliodbs.com> |
| message dated "Fri, 04 Oct 2002 12:09:42 -0700" |
| Date: Fri, 04 Oct 2002 15:45:28 -0400 |
| Message-ID: <26159.1033760728@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/28 |
| X-Sequence-Number: 45 |
| |
| Josh Berkus <josh@agliodbs.com> writes: |
| > When the UPDATE query takes a long time, I generally can watch the log hover |
| > in the land of "Reaping dead child processes" for 30-90 seconds per |
| > iteration. |
| |
| Uh ... would you translate that observation into English please? Or |
| better, provide the log output you're looking at? |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 4 17:02:12 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 022CF47610A |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 17:02:12 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id 66A6C4760B0 |
| for <pgsql-performance@postgresql.org>; |
| Fri, 4 Oct 2002 17:02:11 -0400 (EDT) |
| Received: from [216.135.165.74] (HELO lazarus) |
| by davinci.ethosmedia.com (CommuniGate Pro SMTP 3.5.9) |
| with ESMTP-TLS id 1771959; Fri, 04 Oct 2002 14:00:27 -0700 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Subject: Re: Comparitive UPDATE speed |
| Date: Fri, 4 Oct 2002 14:01:07 -0700 |
| X-Mailer: KMail [version 1.4] |
| Cc: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| References: <1033708425.28946.203.camel@haggis> |
| <200210041113.10008.josh@agliodbs.com> |
| <26113.1033760474@sss.pgh.pa.us> |
| In-Reply-To: <26113.1033760474@sss.pgh.pa.us> |
| MIME-Version: 1.0 |
| Content-Transfer-Encoding: quoted-printable |
| Message-Id: <200210041401.07878.josh@agliodbs.com> |
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| X-Archive-Number: 200210/29 |
| X-Sequence-Number: 46 |
| |
| |
| Tom, |
| |
| > I am suspicious that this table has a huge number of empty pages in it, |
| > mostly at the beginning. If so, a VACUUM FULL would help. (Try |
| > "vacuum full verbose elbs_matter_links" and see if it indicates it's |
| > reclaiming any large number of pages.) |
| |
| Thank you. Aha. |
| |
| That appears to have been the main problem; apparently, at some time during= |
| my=20 |
| tinkering, I dumped most of the rows from elbs_matter_links a couple of=20 |
| times. Ooops. |
| |
| I'll post the new situation when I test the update queries tonight. |
| |
| --=20 |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
| |
| From pgsql-general-owner@postgresql.org Sun Oct 6 11:52:37 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id CCE504761E9; Sun, 6 Oct 2002 11:52:35 -0400 (EDT) |
| Received: from platonic.cynic.net (platonic.cynic.net [204.80.150.245]) |
| by postgresql.org (Postfix) with ESMTP |
| id 5ACF1475F8C; Sun, 6 Oct 2002 11:52:35 -0400 (EDT) |
| Received: from angelic.cynic.net (angelic-platonic.cvpn.cynic.net |
| [198.73.220.226]) by platonic.cynic.net (Postfix) with ESMTP |
| id 65E37BF4C; Sun, 6 Oct 2002 15:52:38 +0000 (UTC) |
| Received: from localhost (localhost [127.0.0.1]) |
| by angelic.cynic.net (Postfix) with ESMTP |
| id 9557F8736; Mon, 7 Oct 2002 00:52:24 +0900 (JST) |
| Date: Mon, 7 Oct 2002 00:52:24 +0900 (JST) |
| From: Curt Sampson <cjs@cynic.net> |
| To: Neil Conway <neilc@samurai.com> |
| Cc: PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org>, |
| PostgresSQL General Mailing List <pgsql-general@postgresql.org> |
| Subject: Re: [HACKERS] Performance while loading data and indexing |
| In-Reply-To: <87n0q4zc0l.fsf@mailbox.samurai.com> |
| Message-ID: <Pine.NEB.4.44.0210070050500.515-100000@angelic.cynic.net> |
| MIME-Version: 1.0 |
| Content-Type: TEXT/PLAIN; charset=US-ASCII |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/324 |
| X-Sequence-Number: 31322 |
| |
| On 26 Sep 2002, Neil Conway wrote: |
| |
| > The fact that ext2 defaults to asynchronous mode and UFS (at least on |
| > the BSDs) defaults to synchronous mode seems like a total non-issue to |
| > me. Is there any more to the alleged difference in reliability? |
| |
| It was sort of pointed out here, but perhaps not made completely |
| clear, that Berkley FFS defaults to synchronous meta-data updates, |
| but asynchronous data updates. You can also specify entirely |
| synchronous or entirely asynchronous updates. Linux ext2fs supports |
| only these last two modes, which is the problem. |
| |
| cjs |
| -- |
| Curt Sampson <cjs@cynic.net> +81 90 7737 2974 http://www.netbsd.org |
| Don't you know, in this new Dark Age, we're all light. --XTC |
| |
| |
| From pgsql-general-owner@postgresql.org Sun Oct 6 22:27:05 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id D2FD7475EE1; Sun, 6 Oct 2002 22:27:03 -0400 (EDT) |
| Received: from platonic.cynic.net (platonic.cynic.net [204.80.150.245]) |
| by postgresql.org (Postfix) with ESMTP |
| id 4E868475E45; Sun, 6 Oct 2002 22:27:03 -0400 (EDT) |
| Received: from angelic.cynic.net (angelic-platonic.cvpn.cynic.net |
| [198.73.220.226]) by platonic.cynic.net (Postfix) with ESMTP |
| id B13B7BF4C; Mon, 7 Oct 2002 02:27:06 +0000 (UTC) |
| Received: from localhost (localhost [127.0.0.1]) |
| by angelic.cynic.net (Postfix) with ESMTP |
| id 752128736; Mon, 7 Oct 2002 11:27:04 +0900 (JST) |
| Date: Mon, 7 Oct 2002 11:27:04 +0900 (JST) |
| From: Curt Sampson <cjs@cynic.net> |
| Reply-To: pgsql-performance@postgresql.org, |
| Curt Sampson <cjs@cynic.net> |
| To: Shridhar Daithankar <shridhar_daithankar@persistent.co.in> |
| Cc: pgsql-general <pgsql-general@postgresql.org>, |
| <pgsql-hackers@postgresql.org> |
| Subject: Re: Large databases, performance |
| In-Reply-To: <3D9CB613.1700.A7DEEF0@localhost> |
| Message-ID: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| MIME-Version: 1.0 |
| Content-Type: TEXT/PLAIN; charset=US-ASCII |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/328 |
| X-Sequence-Number: 31326 |
| |
| On Thu, 3 Oct 2002, Shridhar Daithankar wrote: |
| |
| > Well, we were comparing ext3 v/s reiserfs. I don't remember the journalling |
| > mode of ext3 but we did a 10 GB write test. Besides converting the RAID to RAID- |
| > 0 from RAID-5 might have something to do about it. |
| |
| That will have a massive, massive effect on performance. Depending on |
| your RAID subsystem, you can except RAID-0 to be between two and twenty |
| times as fast for writes as RAID-5. |
| |
| If you compared one filesystem on RAID-5 and another on RAID-0, |
| your results are likely not at all indicative of file system |
| performance. |
| |
| Note that I've redirected followups to the pgsql-performance list. |
| Avoiding cross-posting would be nice, since I am getting lots of |
| duplicate messages these days. |
| |
| cjs |
| -- |
| Curt Sampson <cjs@cynic.net> +81 90 7737 2974 http://www.netbsd.org |
| Don't you know, in this new Dark Age, we're all light. --XTC |
| |
| |
| From pgsql-general-owner@postgresql.org Sun Oct 6 22:30:58 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 9FAE5475C98; Sun, 6 Oct 2002 22:30:56 -0400 (EDT) |
| Received: from platonic.cynic.net (platonic.cynic.net [204.80.150.245]) |
| by postgresql.org (Postfix) with ESMTP |
| id 18880475AAC; Sun, 6 Oct 2002 22:30:56 -0400 (EDT) |
| Received: from angelic.cynic.net (angelic-platonic.cvpn.cynic.net |
| [198.73.220.226]) by platonic.cynic.net (Postfix) with ESMTP |
| id 9383FBF4C; Mon, 7 Oct 2002 02:30:59 +0000 (UTC) |
| Received: from localhost (localhost [127.0.0.1]) |
| by angelic.cynic.net (Postfix) with ESMTP |
| id 13B958736; Mon, 7 Oct 2002 11:30:58 +0900 (JST) |
| Date: Mon, 7 Oct 2002 11:30:57 +0900 (JST) |
| From: Curt Sampson <cjs@cynic.net> |
| Reply-To: pgsql-performance@postgresql.org, |
| Curt Sampson <cjs@cynic.net> |
| To: Shridhar Daithankar <shridhar_daithankar@persistent.co.in> |
| Cc: pgsql-hackers@postgresql.org, pgsql-general <pgsql-general@postgresql.org> |
| Subject: Re: Large databases, performance |
| In-Reply-To: <3D9CB8B3.25411.A882D21@localhost> |
| Message-ID: <Pine.NEB.4.44.0210071127320.443-100000@angelic.cynic.net> |
| MIME-Version: 1.0 |
| Content-Type: TEXT/PLAIN; charset=US-ASCII |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/329 |
| X-Sequence-Number: 31327 |
| |
| On Thu, 3 Oct 2002, Shridhar Daithankar wrote: |
| |
| > Our major concern remains load time as data is generated in real time and is |
| > expecetd in database with in specified time period. |
| |
| If your time period is long enough, you can do what I do, which is |
| to use partial indexes so that the portion of the data being loaded |
| is not indexed. That will speed your loads quite a lot. Aftewards |
| you can either generate another partial index for the range you |
| loaded, or generate a new index over both old and new data, and |
| then drop the old index. |
| |
| The one trick is that the optimizer is not very smart about combining |
| multiple indexes, so you often need to split your queries across |
| the two "partitions" of the table that have separate indexes. |
| |
| > Shall I subscribe to performance? |
| |
| Yes, you really ought to. The list is pgsql-performance@postgresql.org. |
| |
| cjs |
| -- |
| Curt Sampson <cjs@cynic.net> +81 90 7737 2974 http://www.netbsd.org |
| Don't you know, in this new Dark Age, we're all light. --XTC |
| |
| |
| From pgsql-general-owner@postgresql.org Sun Oct 6 23:20:42 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id E7122476141; Sun, 6 Oct 2002 23:20:40 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP |
| id 3D9E8476086; Sun, 6 Oct 2002 23:20:40 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g973KYhR015764; |
| Sun, 6 Oct 2002 23:20:34 -0400 (EDT) |
| To: Curt Sampson <cjs@cynic.net> |
| Cc: pgsql-general <pgsql-general@postgresql.org>, pgsql-hackers@postgresql.org |
| Subject: cross-posts (was Re: Large databases, performance) |
| In-reply-to: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| References: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| Comments: In-reply-to Curt Sampson <cjs@cynic.net> |
| message dated "Mon, 07 Oct 2002 11:27:04 +0900" |
| Date: Sun, 06 Oct 2002 23:20:33 -0400 |
| Message-ID: <15763.1033960833@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/330 |
| X-Sequence-Number: 31328 |
| |
| Curt Sampson <cjs@cynic.net> writes: |
| > ... Avoiding cross-posting would be nice, since I am getting lots of |
| > duplicate messages these days. |
| |
| Cross-posting is a fact of life, and in fact encouraged, on the pg |
| lists. I suggest adapting. Try sending |
| set all unique your-email-address |
| to the PG majordomo server; this sets you up to get only one copy |
| of each cross-posted message. |
| |
| regards, tom lane |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 05:37:06 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1C806476360 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 05:37:04 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id 92204476227 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 05:36:58 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g979cWr08521 |
| for <pgsql-general@postgresql.org>; Mon, 7 Oct 2002 15:08:32 +0530 |
| Received: from daithan (daithan.intranet.pspl.co.in [192.168.7.161]) |
| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g979cWv08510; |
| Mon, 7 Oct 2002 15:08:32 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, pgsql-general <pgsql-general@postgresql.org> |
| Date: Mon, 07 Oct 2002 15:07:29 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-performance@postgresql.org |
| Message-ID: <3DA1A331.21316.F7E742B@localhost> |
| In-reply-to: <3D9C3E05.7070906@clearmetrix.com> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Mail message body |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/337 |
| X-Sequence-Number: 31335 |
| |
| On 3 Oct 2002 at 8:54, Charles H. Woloszynski wrote: |
| |
| > I'd be curious what happens when you submit more queries than you have |
| > processors (you had four concurrent queries and four CPUs), if you care |
| > to run any additional tests. Also, I'd report the query time in |
| > absolute (like you did) and also in 'Time/number of concurrent queries". |
| > This will give you a sense of how the system is scaling as the workload |
| > increases. Personally I am more concerned about this aspect than the |
| > load time, since I am going to guess that this is where all the time is |
| > spent. |
|
|
| OK. I am back from my cave after some more tests are done. Here are the |
| results. I am not repeating large part of it but answering your questions.. |
|
|
| Don't ask me how these numbers changed. I am not the person who conducts the |
| test neither I have access to the system. Rest(or most ) of the things remains |
| same.. |
| |
| MySQL 3.23.52 with innodb transaction support: |
| |
| 4 concurrent queries :- 257.36 ms |
| 40 concurrent queries :- 35.12 ms |
| |
| Postgresql 7.2.2 |
| |
| 4 concurrent queries :- 257.43 ms |
| 40 concurrent queries :- 41.16 ms |
| |
| Though I can not report oracle numbers, suffice to say that they fall in |
| between these two numbers. |
| |
| Oracle seems to be hell lot faster than mysql/postgresql to load raw data even |
| when it's installed on reiserfs. We plan to run XFS tests later in hope that |
| that would improve mysql/postgresql load times. |
|
|
| In this run postgresql has better load time than mysql/innodb ( 18270 sec v/s |
| 17031 sec.) Index creation times are faster as well (100 sec v/s 130 sec). |
| Don't know what parameters are changed. |
| |
| Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All |
| numbers include indexes. This is really going to be a problem when things are |
| deployed. Any idea how can it be taken down? |
| |
| WAL is out, it's not counted. |
|
|
| Schema optimisation is later issue. Right now all three databases are using |
| same schema.. |
|
|
| Will it help in this situation if I recompile posgresql with block size say 32K |
| rather than 8K default? Will it saev some overhead and offer better performance |
| in data load etc? |
|
|
| Will keep you guys updated.. |
|
|
| Regards, |
| Shridhar |
|
|
| |
| Shridhar Daithankar |
| LIMS CPE Team Member, PSPL. |
| mailto:shridhar_daithankar@persistent.co.in |
| Phone:- +91-20-5678900 Extn.270 |
| Fax :- +91-20-5678901 |
| |
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 08:24:37 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id BEF1D475B8F |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 06:00:41 -0400 (EDT) |
| Received: from bachata.cybertec.at (unknown [62.116.21.146]) |
| by postgresql.org (Postfix) with SMTP id 35A79475921 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 06:00:40 -0400 (EDT) |
| Received: (qmail 4501 invoked from network); 7 Oct 2002 10:00:44 -0000 |
| Received: from unknown (HELO cybertec.at) (62.116.21.147) |
| by 62.116.21.146 with SMTP; 7 Oct 2002 10:00:44 -0000 |
| Message-ID: <3DA15B7C.8010005@cybertec.at> |
| Date: Mon, 07 Oct 2002 12:01:32 +0200 |
| From: =?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <hs@cybertec.at> |
| User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20020830 |
| X-Accept-Language: en-us, en |
| MIME-Version: 1.0 |
| To: shridhar_daithankar@persistent.co.in, |
| pgsql-general@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| References: <3DA1A331.21316.F7E742B@localhost> |
| Content-Type: text/plain; charset=us-ascii; format=flowed |
| Content-Transfer-Encoding: 7bit |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/355 |
| X-Sequence-Number: 31353 |
|
|
| I wonder if the following changes make a difference: |
|
|
| - compile PostgreSQL with CFLAGS=' -O3 ' |
| - redefine commit delays |
|
|
| also: keep in mind that you might gain a lot of performance by using the |
| SPI if you are running many similar queries |
|
|
| try 7.3 - as far as I remeber there is a mechanism which caches recent |
| execution plans. |
| also: some overhead was reduced (tuples, backend startup). |
|
|
| Hans |
|
|
|
|
| >Ok. I am back from my cave after some more tests are done. Here are the |
| >results. I am not repeating large part of it but answering your questions.. |
| > |
| >Don't ask me how these numbers changed. I am not the person who conducts the |
| >test neither I have access to the system. Rest(or most ) of the things remains |
| >same.. |
| > |
| >MySQL 3.23.52 with innodb transaction support: |
| > |
| >4 concurrent queries :- 257.36 ms |
| >40 concurrent queries :- 35.12 ms |
| > |
| >Postgresql 7.2.2 |
| > |
| >4 concurrent queries :- 257.43 ms |
| >40 concurrent queries :- 41.16 ms |
| > |
| >Though I can not report oracle numbers, suffice to say that they fall in |
| >between these two numbers. |
| > |
| >Oracle seems to be hell lot faster than mysql/postgresql to load raw data even |
| >when it's installed on reiserfs. We plan to run XFS tests later in hope that |
| >that would improve mysql/postgresql load times. |
| > |
| >In this run postgresql has better load time than mysql/innodb ( 18270 sec v/s |
| >17031 sec.) Index creation times are faster as well (100 sec v/s 130 sec). |
| >Don't know what parameters are changed. |
| > |
| >Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All |
| >numbers include indexes. This is really going to be a problem when things are |
| >deployed. Any idea how can it be taken down? |
| > |
| >WAL is out, it's not counted. |
| > |
| >Schema optimisation is later issue. Right now all three databases are using |
| >same schema.. |
| > |
| >Will it help in this situation if I recompile posgresql with block size say 32K |
| >rather than 8K default? Will it saev some overhead and offer better performance |
| >in data load etc? |
| > |
| >Will keep you guys updated.. |
| > |
| >Regards, |
| > Shridhar |
| > |
| > |
| >Shridhar Daithankar |
| >LIMS CPE Team Member, PSPL. |
| >mailto:shridhar_daithankar@persistent.co.in |
| >Phone:- +91-20-5678900 Extn.270 |
| >Fax :- +91-20-5678901 |
| > |
| > |
| > |
| > |
| >TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org |
| > |
| > |
|
|
|
|
| |
| *Cybertec Geschwinde u Schoenig* |
| Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria |
| Tel: +43/1/913 68 09; +43/664/233 90 75 |
| www.postgresql.at <http://www.postgresql.at>, cluster.postgresql.at |
| <http://cluster.postgresql.at>, www.cybertec.at |
| <http://www.cybertec.at>, kernel.cybertec.at <http://kernel.cybertec.at> |
|
|
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 07:51:14 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 0F7B5475F4F; Mon, 7 Oct 2002 07:51:13 -0400 (EDT) |
| Received: from lerlaptop.iadfw.net (pppth08-291.ght.iadfw.net |
| [207.136.52.165]) |
| by postgresql.org (Postfix) with ESMTP |
| id 45FC8475D1C; Mon, 7 Oct 2002 07:51:10 -0400 (EDT) |
| Received: from localhost (localhost [127.0.0.1]) |
| by lerlaptop.iadfw.net (8.12.6/8.12.5) with ESMTP id g97Boxnk000463; |
| Mon, 7 Oct 2002 06:51:00 -0500 (CDT) (envelope-from ler@lerctr.org) |
| Subject: Re: [HACKERS] cross-posts (was Re: Large databases, |
| From: Larry Rosenman <ler@lerctr.org> |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Cc: Curt Sampson <cjs@cynic.net>, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-hackers@postgresql.org |
| In-Reply-To: <15763.1033960833@sss.pgh.pa.us> |
| References: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| <15763.1033960833@sss.pgh.pa.us> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 07 Oct 2002 06:50:59 -0500 |
| Message-Id: <1033991460.311.6.camel@lerlaptop> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by amavisd-milter (http://amavis.org/) |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/339 |
| X-Sequence-Number: 31337 |
|
|
| On Sun, 2002-10-06 at 22:20, Tom Lane wrote: |
| > Curt Sampson <cjs@cynic.net> writes: |
| > > ... Avoiding cross-posting would be nice, since I am getting lots of |
| > > duplicate messages these days. |
| > |
| > Cross-posting is a fact of life, and in fact encouraged, on the pg |
| > lists. I suggest adapting. Try sending |
| > set all unique your-email-address |
| > to the PG majordomo server; this sets you up to get only one copy |
| > of each cross-posted message. |
| That doesn't seem to work any more: |
| |
| >>>> set all unique ler@lerctr.org |
| **** The "all" mailing list is not supported at |
| **** PostgreSQL User Support Lists. |
| |
| What do I need to send now? |
| |
| Marc? |
| |
| |
| -- |
| Larry Rosenman http://www.lerctr.org/~ler |
| Phone: +1 972-414-9812 E-Mail: ler@lerctr.org |
| US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749 |
| |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 08:22:17 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id B9D89475F86 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 07:59:05 -0400 (EDT) |
| Received: from mail.gmx.net (mail.gmx.net [213.165.64.20]) |
| by postgresql.org (Postfix) with SMTP id 00081475AE5 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 07:59:03 -0400 (EDT) |
| Received: (qmail 24764 invoked by uid 0); 7 Oct 2002 11:59:06 -0000 |
| Received: from chello062178186201.1.15.tuwien.teleweb.at (HELO beeblebrox) |
| (62.178.186.201) |
| by mail.gmx.net (mp008-rz3) with SMTP; 7 Oct 2002 11:59:06 -0000 |
| Message-ID: <00f801c26df9$44465720$4201a8c0@beeblebrox> |
| From: "Michael Paesold" <mpaesold@gmx.at> |
| To: "Larry Rosenman" <ler@lerctr.org>, "Tom Lane" <tgl@sss.pgh.pa.us> |
| Cc: "Curt Sampson" <cjs@cynic.net>, |
| "pgsql-general" <pgsql-general@postgresql.org>, |
| <pgsql-hackers@postgresql.org> |
| References: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| <15763.1033960833@sss.pgh.pa.us> <1033991460.311.6.camel@lerlaptop> |
| Subject: Re: [HACKERS] cross-posts (was Re: Large databases, |
| Date: Mon, 7 Oct 2002 14:01:25 +0200 |
| MIME-Version: 1.0 |
| Content-Type: text/plain; |
| charset="Windows-1252" |
| Content-Transfer-Encoding: 7bit |
| X-Priority: 3 |
| X-MSMail-Priority: Normal |
| X-Mailer: Microsoft Outlook Express 6.00.2600.0000 |
| X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/353 |
| X-Sequence-Number: 31351 |
| |
| > On Sun, 2002-10-06 at 22:20, Tom Lane wrote: |
| > > Curt Sampson <cjs@cynic.net> writes: |
| > > > ... Avoiding cross-posting would be nice, since I am getting lots of |
| > > > duplicate messages these days. |
| > > |
| > > Cross-posting is a fact of life, and in fact encouraged, on the pg |
| > > lists. I suggest adapting. Try sending |
| > > set all unique your-email-address |
| > > to the PG majordomo server; this sets you up to get only one copy |
| > > of each cross-posted message. |
| > That doesn't seem to work any more: |
| > |
| > >>>> set all unique ler@lerctr.org |
| > **** The "all" mailing list is not supported at |
| > **** PostgreSQL User Support Lists. |
| > |
| > What do I need to send now? |
| > |
| > Marc? |
|
|
| it is: |
| set ALL unique your-email |
|
|
| if you also don't want to get emails that have already been cc'd to you, you |
| can use: |
|
|
| set ALL eliminatecc your-email |
|
|
| for a full list of set options send: |
|
|
| help set |
|
|
| to majordomo. |
|
|
| Regards, |
| Michael Paesold |
|
|
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 08:04:46 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 6D474475F86; Mon, 7 Oct 2002 08:04:45 -0400 (EDT) |
| Received: from lerlaptop.iadfw.net (pppth08-291.ght.iadfw.net |
| [207.136.52.165]) |
| by postgresql.org (Postfix) with ESMTP |
| id 25F40475F4F; Mon, 7 Oct 2002 08:04:44 -0400 (EDT) |
| Received: from localhost (localhost [127.0.0.1]) |
| by lerlaptop.iadfw.net (8.12.6/8.12.5) with ESMTP id g97C4Xnk000539; |
| Mon, 7 Oct 2002 07:04:34 -0500 (CDT) (envelope-from ler@lerctr.org) |
| Subject: Re: [HACKERS] cross-posts (was Re: Large databases, |
| From: Larry Rosenman <ler@lerctr.org> |
| To: Michael Paesold <mpaesold@gmx.at> |
| Cc: Tom Lane <tgl@sss.pgh.pa.us>, Curt Sampson <cjs@cynic.net>, |
| pgsql-general <pgsql-general@postgresql.org>, pgsql-hackers@postgresql.org |
| In-Reply-To: <00f801c26df9$44465720$4201a8c0@beeblebrox> |
| References: <Pine.NEB.4.44.0210071124410.443-100000@angelic.cynic.net> |
| <15763.1033960833@sss.pgh.pa.us> <1033991460.311.6.camel@lerlaptop> |
| <00f801c26df9$44465720$4201a8c0@beeblebrox> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 07 Oct 2002 07:04:33 -0500 |
| Message-Id: <1033992275.311.12.camel@lerlaptop> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by amavisd-milter (http://amavis.org/) |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/340 |
| X-Sequence-Number: 31338 |
|
|
| On Mon, 2002-10-07 at 07:01, Michael Paesold wrote: |
| > > On Sun, 2002-10-06 at 22:20, Tom Lane wrote: |
| > > > Curt Sampson <cjs@cynic.net> writes: |
| > > > > ... Avoiding cross-posting would be nice, since I am getting lots of |
| > > > > duplicate messages these days. |
| > > > |
| > > > Cross-posting is a fact of life, and in fact encouraged, on the pg |
| > > > lists. I suggest adapting. Try sending |
| > > > set all unique your-email-address |
| > > > to the PG majordomo server; this sets you up to get only one copy |
| > > > of each cross-posted message. |
| > > That doesn't seem to work any more: |
| > > |
| > > >>>> set all unique ler@lerctr.org |
| > > **** The "all" mailing list is not supported at |
| > > **** PostgreSQL User Support Lists. |
| > > |
| > > What do I need to send now? |
| > > |
| > > Marc? |
| > |
| > it is: |
| > set ALL unique your-email |
| > |
| > if you also don't want to get emails that have already been cc'd to you, you |
| > can use: |
| > |
| > set ALL eliminatecc your-email |
| > |
| > for a full list of set options send: |
| > |
| > help set |
| > |
| > to majordomo. |
| Thanks. That worked great. (I use Mailman, and didn't realize the ALL |
| needed to be capitalized. |
|
|
| LER |
|
|
|
|
| |
| Larry Rosenman http://www.lerctr.org/~ler |
| Phone: +1 972-414-9812 E-Mail: ler@lerctr.org |
| US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749 |
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 10:07:55 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 9AA5A4768CE |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 10:07:54 -0400 (EDT) |
| Received: from email01.aon.at (WARSL402PIP3.highway.telekom.at [195.3.96.97]) |
| by postgresql.org (Postfix) with SMTP id 3E3D647681A |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 10:07:52 -0400 (EDT) |
| Received: (qmail 167656 invoked from network); 7 Oct 2002 14:07:55 -0000 |
| Received: from m157p026.dipool.highway.telekom.at (HELO cantor) |
| ([62.46.9.154]) (envelope-sender <mkoi-pg@aon.at>) |
| by qmail1rs.highway.telekom.at (qmail-ldap-1.03) with SMTP |
| for <shridhar?daithankar@persistent.co.in>; 7 Oct 2002 14:07:55 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Large databases, performance |
| Date: Mon, 07 Oct 2002 16:10:26 +0200 |
| Message-ID: <69v2qu4n8fdt5do8dids2a9m98p0q8bu9r@4ax.com> |
| References: <3D9C3E05.7070906@clearmetrix.com> |
| <3DA1A331.21316.F7E742B@localhost> |
| In-Reply-To: <3DA1A331.21316.F7E742B@localhost> |
| X-Mailer: Forte Agent 1.8/32.548 |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
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| X-Archive-Number: 200210/378 |
| X-Sequence-Number: 31376 |
|
|
| On Mon, 07 Oct 2002 15:07:29 +0530, "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> wrote: |
| >Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All |
| >numbers include indexes. This is really going to be a problem when things are |
| >deployed. Any idea how can it be taken down? |
|
|
| Shridhar, |
|
|
| if i'm not mistaken, a char(n)/varchar(n) column is stored as a 32-bit |
| integer specifying the length followed by as many characters as the |
| length tells. On 32-bit Intel hardware this structure is aligned on a |
| 4-byte boundary. |
| |
| For your row layout this gives the following sizes (look at the "phys |
| size" column): |
| |
| | Field Field Null Indexed phys mini |
| | Name Type size |
| |-------------------------------------------- |
| | type int no no 4 4 |
| | esn char (10) no yes 16 11 |
| | min char (10) no yes 16 11 |
| | datetime timestamp no yes 8 8 |
| | opc0 char (3) no no 8 4 |
| | opc1 char (3) no no 8 4 |
| | opc2 char (3) no no 8 4 |
| | dpc0 char (3) no no 8 4 |
| | dpc1 char (3) no no 8 4 |
| | dpc2 char (3) no no 8 4 |
| | npa char (3) no no 8 4 |
| | nxx char (3) no no 8 4 |
| | rest char (4) no no 8 5 |
| | field0 int yes no 4 4 |
| | field1 char (4) yes no 8 5 |
| | field2 int yes no 4 4 |
| | field3 char (4) yes no 8 5 |
| | field4 int yes no 4 4 |
| | field5 char (4) yes no 8 5 |
| | field6 int yes no 4 4 |
| | field7 char (4) yes no 8 5 |
| | field8 int yes no 4 4 |
| | field9 char (4) yes no 8 5 |
| | ----- ----- |
| | 176 116 |
| |
| Ignoring nulls for now, you have to add 32 bytes for a v7.2 heap tuple |
| header and 4 bytes for ItemIdData per tuple, ending up with 212 bytes |
| per tuple or ca. 85 GB heap space for 432000000 tuples. Depending on |
| fill factor similar calculations give some 30 GB for your index. |
| |
| Now if we had a datatype with only one byte for the string length, |
| char columns could be byte aligned and we'd have column sizes given |
| under "mini" in the table above. The columns would have to be |
| rearranged according to alignment requirements. |
|
|
| Thus 60 bytes per heap tuple and 8 bytes per index tuple could be |
| saved, resulting in a database size of ~ 85 GB (index included). And |
| I bet this would be significantly faster, too. |
|
|
| Hackers, do you think it's possible to hack together a quick and dirty |
| patch, so that string length is represented by one byte? IOW can a |
| database be built that doesn't contain any char/varchar/text value |
| longer than 255 characters in the catalog? |
|
|
| If I'm not told that this is impossibly, I'd give it a try. Shridhar, |
| if such a patch can be made available, would you be willing to test |
| it? |
|
|
| What can you do right now? Try using v7.3 beta and creating your |
| table WITHOUT OIDS. This saves 8 bytes per tuple; not much, but |
| better save 4% than nothing. |
|
|
| Servus |
| Manfred |
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 10:18:03 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id BE7454768BE |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 10:18:01 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id 6D85C476663 |
| for <pgsql-general@postgresql.org>; |
| Mon, 7 Oct 2002 10:17:59 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g97EJar08753 |
| for <pgsql-general@postgresql.org>; Mon, 7 Oct 2002 19:49:36 +0530 |
| Received: from daithan (daithan.intranet.pspl.co.in [192.168.7.161]) |
| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g97EJav08731; |
| Mon, 7 Oct 2002 19:49:36 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Mon, 07 Oct 2002 19:48:31 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA1E50F.4394.107FF85D@localhost> |
| In-reply-to: <69v2qu4n8fdt5do8dids2a9m98p0q8bu9r@4ax.com> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Mail message body |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/382 |
| X-Sequence-Number: 31380 |
|
|
| On 7 Oct 2002 at 16:10, Manfred Koizar wrote: |
| > if i'm not mistaken, a char(n)/varchar(n) column is stored as a 32-bit |
| > integer specifying the length followed by as many characters as the |
| > length tells. On 32-bit Intel hardware this structure is aligned on a |
| > 4-byte boundary. |
| |
| That shouldn't be necessary for a char field as space is always pre-allocated. |
| Sounds like a possible area of imporvement to me, if that's the case.. |
| |
| > Hackers, do you think it's possible to hack together a quick and dirty |
| > patch, so that string length is represented by one byte? IOW can a |
| > database be built that doesn't contain any char/varchar/text value |
| > longer than 255 characters in the catalog? |
| |
| I say if it's a char field, there should be no indicator of length as it's not |
| required. Just store those many characters straight ahead.. |
| |
| > |
| > If I'm not told that this is impossibly, I'd give it a try. Shridhar, |
| > if such a patch can be made available, would you be willing to test |
| > it? |
| |
| Sure. But the server machine is not available this week. Some other project is |
| using it. So the results won't be out unless at least a week from now. |
|
|
|
|
| > What can you do right now? Try using v7.3 beta and creating your |
| > table WITHOUT OIDS. This saves 8 bytes per tuple; not much, but |
| > better save 4% than nothing. |
|
|
| IIRC there was some header optimisation which saved 4 bytes. So without OIDs |
| that should save 8. Would do that as first next thing. |
|
|
| I talked to my friend regarding postgresql surpassing mysql substantially in |
| this test. He told me that the last test where postgresql took 23000+/150 sec |
| for load/index and mysql took 18,000+/130 index, postgresql was running in |
| default configuration. He forgot to copy postgresql.conf to data directory |
| after he modified it. |
|
|
| This time results are correct. Postgresql loads data faster, indexes it faster |
| and queries in almost same time.. Way to go.. |
|
|
| Regards, |
| Shridhar |
|
|
| |
| Shridhar Daithankar |
| LIMS CPE Team Member, PSPL. |
| mailto:shridhar_daithankar@persistent.co.in |
| Phone:- +91-20-5678900 Extn.270 |
| Fax :- +91-20-5678901 |
| |
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 10:32:46 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 981564764F9; Mon, 7 Oct 2002 10:32:44 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP |
| id 2F37E476879; Mon, 7 Oct 2002 10:30:55 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g97EUbhR023490; |
| Mon, 7 Oct 2002 10:30:37 -0400 (EDT) |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| In-reply-to: <3DA1A331.21316.F7E742B@localhost> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| Comments: In-reply-to "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> |
| message dated "Mon, 07 Oct 2002 15:07:29 +0530" |
| Date: Mon, 07 Oct 2002 10:30:37 -0400 |
| Message-ID: <23489.1034001037@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/383 |
| X-Sequence-Number: 31381 |
|
|
| "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > MySQL 3.23.52 with innodb transaction support: |
|
|
| > 4 concurrent queries :- 257.36 ms |
| > 40 concurrent queries :- 35.12 ms |
|
|
| > Postgresql 7.2.2 |
|
|
| > 4 concurrent queries :- 257.43 ms |
| > 40 concurrent queries :- 41.16 ms |
|
|
| I find this pretty fishy. The extreme similarity of the 4-client |
| numbers seems improbable, from what I know of the two databases. |
| I suspect your numbers are mostly measuring some non-database-related |
| overhead |
|
|
| > Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All |
| > numbers include indexes. This is really going to be a problem when things are |
| > deployed. Any idea how can it be taken down? |
|
|
| 7.3 should be a little bit better because of Manfred's work on reducing |
| tuple header size --- if you create your tables WITHOUT OIDS, you should |
| save 8 bytes per row compared to earlier releases. |
| |
| regards, tom lane |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 10:39:28 2002 |
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| Mon, 7 Oct 2002 20:10:59 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Mon, 07 Oct 2002 20:09:55 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [pgsql-performance] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA1EA13.16626.10939155@localhost> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| In-reply-to: <23489.1034001037@sss.pgh.pa.us> |
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| |
| On 7 Oct 2002 at 10:30, Tom Lane wrote: |
| |
| > "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > > MySQL 3.23.52 with innodb transaction support: |
| > |
| > > 4 concurrent queries :- 257.36 ms |
| > > 40 concurrent queries :- 35.12 ms |
| > |
| > > Postgresql 7.2.2 |
| > |
| > > 4 concurrent queries :- 257.43 ms |
| > > 40 concurrent queries :- 41.16 ms |
| > |
| > I find this pretty fishy. The extreme similarity of the 4-client |
| > numbers seems improbable, from what I know of the two databases. |
| > I suspect your numbers are mostly measuring some non-database-related |
| > overhead --- communications overhead, maybe? |
| |
| I don't know but three numbers, postgresql/mysql/oracle all are 25x.xx ms. The |
| clients were on same machie as of server. So no real area to point at.. |
| > |
| > > Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All |
| > > numbers include indexes. This is really going to be a problem when things are |
| > > deployed. Any idea how can it be taken down? |
| > |
| > 7.3 should be a little bit better because of Manfred's work on reducing |
| > tuple header size --- if you create your tables WITHOUT OIDS, you should |
| > save 8 bytes per row compared to earlier releases. |
| |
| Got it.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| Sweater, n.: A garment worn by a child when its mother feels chilly. |
| |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 11:22:09 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 0069A47621C; Mon, 7 Oct 2002 11:22:09 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP |
| id 520A5476720; Mon, 7 Oct 2002 11:21:58 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g97FLvhR023898; |
| Mon, 7 Oct 2002 11:21:57 -0400 (EDT) |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| In-reply-to: <3DA1E50F.4394.107FF85D@localhost> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| <3DA1E50F.4394.107FF85D@localhost> |
| Comments: In-reply-to "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> |
| message dated "Mon, 07 Oct 2002 19:48:31 +0530" |
| Date: Mon, 07 Oct 2002 11:21:57 -0400 |
| Message-ID: <23897.1034004117@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/390 |
| X-Sequence-Number: 31388 |
| |
| "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > I say if it's a char field, there should be no indicator of length as |
| > it's not required. Just store those many characters straight ahead.. |
| |
| Your assumption fails when considering UNICODE or other multibyte |
| character encodings. |
| |
| regards, tom lane |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 7 11:20:14 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 11:20:13 -0400 (EDT) |
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| Mon, 7 Oct 2002 11:20:08 -0400 (EDT) |
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| for <shridhar?daithankar@persistent.co.in>; 7 Oct 2002 15:20:09 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Large databases, performance |
| Date: Mon, 07 Oct 2002 17:22:41 +0200 |
| Message-ID: <cl83quoi1kt2ebcsbajm18iekkporrj9f5@4ax.com> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| <69v2qu4n8fdt5do8dids2a9m98p0q8bu9r@4ax.com> |
| <3DA1E50F.4394.107FF85D@localhost> |
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| |
| On Mon, 07 Oct 2002 19:48:31 +0530, "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> wrote: |
| >I say if it's a char field, there should be no indicator of length as it's not |
| >required. Just store those many characters straight ahead.. |
| |
| This is out of reach for a quick hack ... |
| |
| >Sure. But the server machine is not available this week. Some other project is |
| >using it. So the results won't be out unless at least a week from now. |
|
|
| :-) |
|
|
| >This time results are correct. Postgresql loads data faster, indexes it faster |
| >and queries in almost same time.. Way to go.. |
|
|
| Great! And now let's work on making selects faster, too. |
| |
| Servus |
| Manfred |
| |
| From pgsql-general-owner@postgresql.org Tue Oct 8 12:37:36 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Subject: Re: [HACKERS] Large databases, performance |
| Date: Mon, 7 Oct 2002 17:42:12 +0200 |
| Message-ID: <46C15C39FEB2C44BA555E356FBCD6FA4887A5A@m0114.s-mxs.net> |
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| Thread-Topic: [HACKERS] [GENERAL] Large databases, performance |
| Thread-Index: AcJuC2mXfpTsQsS8SYipEwKJNAatyAADFkzQ |
| From: "Zeugswetter Andreas SB SD" <ZeugswetterA@spardat.at> |
| To: "Manfred Koizar" <mkoi-pg@aon.at>, <shridhar_daithankar@persistent.co.in> |
| Cc: <pgsql-hackers@postgresql.org>, |
| "pgsql-general" <pgsql-general@postgresql.org>, |
| <pgsql-performance@postgresql.org> |
| X-OriginalArrivalTime: 07 Oct 2002 15:42:12.0994 (UTC) |
| FILETIME=[1AEF0E20:01C26E18] |
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| |
| |
| > if i'm not mistaken, a char(n)/varchar(n) column is stored as a 32-bit |
| > integer specifying the length followed by as many characters as the |
| > length tells. On 32-bit Intel hardware this structure is aligned on a |
| > 4-byte boundary. |
|
|
| Yes. |
|
|
| > | opc0 char (3) no no 8 4 |
| > | opc1 char (3) no no 8 4 |
| > | opc2 char (3) no no 8 4 |
|
|
| > Hackers, do you think it's possible to hack together a quick and dirty |
| > patch, so that string length is represented by one byte? IOW can a |
| > database be built that doesn't contain any char/varchar/text value |
| > longer than 255 characters in the catalog? |
|
|
| Since he is only using fixchar how about doing a fixchar implemetation, tha= |
| t=20 |
| does not store length at all ? It is the same for every row anyways ! |
|
|
| Andreas |
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 15:21:11 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 11E9B4768E9; Mon, 7 Oct 2002 15:21:11 -0400 (EDT) |
| Received: from edisonaffiliates.com (w205.z208176060.chi-il.dsl.cnc.net |
| [208.176.60.205]) by postgresql.org (Postfix) with SMTP |
| id 04BA947671D; Mon, 7 Oct 2002 15:19:54 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 14:15:01 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Pgsql-General@Postgresql. Org" <pgsql-general@postgresql.org>, |
| <pgsql-performance@postgresql.org> |
| Subject: sloooow query |
| Date: Mon, 7 Oct 2002 14:22:09 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEKEAPCJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| Hello all, |
|
|
| I am experiencing slow db performance. I have vacuumed, analyzed, reindexed |
| using the force option and performance remains the same - dog-slow :( If I |
| drop and recreate the database, performance is normal, so this suggests a |
| problem with the indexes? I also took a look at the postgresql.conf and all |
| appears fine. There are many instances of the same database running on |
| different servers and not all servers are experiencing the problem. |
|
|
| Thanks in advance for any suggestions. |
|
|
| Marie |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 15:26:53 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 739A447691D |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 15:26:52 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id A46524768E9 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 15:26:51 -0400 (EDT) |
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| with ESMTP id 1774269; Mon, 07 Oct 2002 12:25:23 -0700 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Reply-To: josh@agliodbs.com |
| Organization: Aglio Database Solutions |
| To: <marie.tuite@edisonaffiliates.com>, |
| <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 12:29:17 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <IGELKLINGDMODABPOOFEKEAPCJAA.marie.tuite@edisonaffiliates.com> |
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|
|
|
|
| Marie, |
|
|
| > I am experiencing slow db performance. I have vacuumed, analyzed, reinde= |
| xed |
| > using the force option and performance remains the same - dog-slow :( If= |
| I |
| > drop and recreate the database, performance is normal, so this suggests a |
| > problem with the indexes? I also took a look at the postgresql.conf and = |
| all |
| > appears fine. There are many instances of the same database running on |
| > different servers and not all servers are experiencing the problem. |
|
|
| Please post the following: |
| 1) A copy of the relevant portions of your database schema. |
| 2) The query that is running slowly. |
| 3) The results of running EXPLAIN on that query. |
| 4) Your PostgreSQL version and operating system |
| 5) Any other relevant information about your databases, such as the quantit= |
| y=20 |
| of inserts and deletes on the relevant tables. |
|
|
| |
| -Josh Berkus |
| Aglio Database Solutions |
| San Francisco |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 15:30:09 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 62DD5475F80 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 15:30:08 -0400 (EDT) |
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| by new-smtp2.ihug.com.au with esmtp (Exim 3.22 |
| id 17ydZt-0006Ew-00; Tue, 08 Oct 2002 05:30:05 +1000 |
| Message-ID: <3DA1E0BB.236FCC17@postgresql.org> |
| Date: Tue, 08 Oct 2002 05:30:03 +1000 |
| From: Justin Clift <justin@postgresql.org> |
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| To: josh@agliodbs.com |
| Cc: marie.tuite@edisonaffiliates.com, |
| pgsql-performance@postgresql.org |
| Subject: Re: sloooow query |
| References: <IGELKLINGDMODABPOOFEKEAPCJAA.marie.tuite@edisonaffiliates.com> |
| <200210071229.17873.josh@agliodbs.com> |
| Content-Type: text/plain; charset=us-ascii |
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| X-Archive-Number: 200210/40 |
| X-Sequence-Number: 57 |
|
|
| Josh Berkus wrote: |
| > |
| > Marie, |
| > |
| > > I am experiencing slow db performance. I have vacuumed, analyzed, reindexed |
| > > using the force option and performance remains the same - dog-slow :( If I |
| > > drop and recreate the database, performance is normal, so this suggests a |
| > > problem with the indexes? I also took a look at the postgresql.conf and all |
| > > appears fine. There are many instances of the same database running on |
| > > different servers and not all servers are experiencing the problem. |
| > |
| > Please post the following: |
| > 1) A copy of the relevant portions of your database schema. |
| > 2) The query that is running slowly. |
| > 3) The results of running EXPLAIN on that query. |
| > 4) Your PostgreSQL version and operating system |
| > 5) Any other relevant information about your databases, such as the quantity |
| > of inserts and deletes on the relevant tables. |
|
|
| 6) And the sort_mem, shared_buffers, vacuum_mem, wal_buffers, and |
| wal_files settings from your postgresql.conf file, if possible. |
|
|
| :-) |
|
|
| Regards and best wishes, |
|
|
| Justin Clift |
|
|
| |
| > |
| > -Josh Berkus |
| > Aglio Database Solutions |
| > San Francisco |
| > |
| > |
| > TIP 5: Have you checked our extensive FAQ? |
| > |
| > http://www.postgresql.org/users-lounge/docs/faq.html |
|
|
| |
| "My grandfather once told me that there are two kinds of people: those |
| who work and those who take the credit. He told me to try to be in the |
| first group; there was less competition there." |
| - Indira Gandhi |
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 15:46:58 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 8EA88475FC6 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 15:46:56 -0400 (EDT) |
| Received: from edisonaffiliates.com (w205.z208176060.chi-il.dsl.cnc.net |
| [208.176.60.205]) |
| by postgresql.org (Postfix) with SMTP id A9A2E475F80 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 15:46:55 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 14:42:08 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 14:49:16 -0500 |
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|
|
| Josh, |
|
|
| Thanks for the reply. |
|
|
| I pg_dumped the first database having performance problems and reloaded it |
| into a new database on the same server. The query ran normally when I |
| reloaded it. There is no difference in hardware, schema or anything else. |
|
|
| project= |
| version |
| |
| PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC 2.96 |
| (1 row) |
|
|
| [mtuite@area52 mtuite]$ uname -a |
| Linux area52.spacedock.com 2.4.7-10 |
| unknown |
|
|
|
|
| Below is the explain for the reload. |
|
|
| bm221= |
| psql:bad.qry:78: NOTICE: QUERY PLAN: |
|
|
| Sort (cost=273.71..273.71 rows=1 width=237) (actual time=143.82..143.96 |
| rows=181 loops=1) |
| -> Group (cost=273.53..273.70 rows=1 width=237) (actual |
| time=136.98..140.78 rows=181 loops=1) |
| -> Sort (cost=273.53..273.53 rows=7 width=237) (actual |
| time=136.95..137.11 rows=181 loops=1) |
| -> Merge Join (cost=273.37..273.43 rows=7 width=237) (actual |
| time=124.41..129.72 rows=181 loops=1) |
| -> Sort (cost=162.24..162.24 rows=7 width=216) (actual |
| time=51.83..52.00 rows=181 loops=1) |
| -> Subquery Scan student_set |
| (cost=161.09..162.14 rows=7 width=216) (actual time=48.12..50.49 rows=181 |
| loops=1) |
| -> Unique (cost=161.09..162.14 rows=7 |
| width=216) (actual time=48.10..49.45 rows=181 loops=1) |
| -> Sort (cost=161.09..161.09 rows=70 |
| width=216) (actual time=48.09..48.26 rows=181 loops=1) |
| -> Hash Join |
| (cost=130.58..158.96 rows=70 width=216) (actual time=43.26..47.11 rows=181 |
| loops=1) |
| -> Seq Scan on classes c |
| (cost=0.00..20.00 rows=1000 width=72) (actual time=0.12..1.78 rows=332 |
| loops=1) |
| -> Hash |
| (cost=130.55..130.55 rows=14 width=144) (actual time=43.02..43.02 rows=0 |
| loops=1) |
| -> Hash Join |
| (cost=105.38..130.55 rows=14 width=144) (actual time=31.13..42.44 rows=181 |
| loops=1) |
| -> Seq Scan |
| on user_common uc (cost=0.00..20.00 rows=1000 width=80) (actual |
| time=0.12..7.07 rows=1045 loops=1) |
| -> Hash |
| (cost=105.37..105.37 rows=3 width=64) (actual time=30.91..30.91 rows=0 |
| loops=1) |
| -> Hash |
| Join (cost=77.46..105.37 rows=3 width=64) (actual time=4.79..30.46 rows=181 |
| loops=1) |
| -> |
| Seq Scan on student_class_rlt scr (cost=0.00..22.50 rows=995 width=24) |
| (actual time=0.25..23.74 rows=527 loops=1) |
| -> |
| Hash (cost=77.45..77.45 rows=5 width=40) (actual time=4.02..4.02 rows=0 |
| loops=1) |
| |
| -> Hash Join (cost=52.38..77.45 rows=5 width=40) (actual |
| time=3.28..3.96 rows=27 loops=1) |
| |
| -> Seq Scan on bm_subscriptions_rlt bsr (cost=0.00..20.00 |
| rows=1000 width=8) (actual time=0.11..0.47 rows=114 loops=1) |
| |
| -> Hash (cost=52.38..52.38 rows=1 width=32) (actual |
| time=3.10..3.10 rows=0 loops=1) |
| |
| -> Hash Join (cost=4.83..52.38 rows=1 width=32) (actual |
| time=2.23..3.07 rows=11 loops=1) |
| |
| -> Seq Scan on bm_publications bp (cost=0.00..47.50 |
| rows=11 width=12) (actual time=1.49..2.25 rows=11 loops=1) |
|
|
| -> Hash (cost=4.82..4.82 rows=1 width=20) (actual time=0.63..0.63 |
| rows=0 loops=1) |
| |
| -> Index Scan using bm_publication_events_pkey |
| on bm_publication_events bpe (cost=0.00..4.82 rows=1 width=20) (actual |
| time=0.60..0.61 rows=1 loops=1) |
| -> Sort (cost=111.13..111.13 rows=18 width=21) (actual |
| time=72.51..73.15 rows=770 loops=1) |
| -> Subquery Scan participation_set |
| (cost=22.51..110.75 rows=18 width=21) (actual time=1.32..57.28 rows=809 |
| loops=1) |
| -> Hash Join (cost=22.51..110.75 rows=18 |
| width=21) (actual time=1.30..52.21 rows=809 loops=1) |
| -> Seq Scan on bm_user_results bur |
| (cost=0.00..70.01 rows=3601 width=17) (actual time=0.14..18.53 rows=3601 |
| loops=1) |
| -> Hash (cost=22.50..22.50 rows=5 |
| width=4) (actual time=0.91..0.91 rows=0 loops=1) |
| -> Seq Scan on bm_publications |
| bp (cost=0.00..22.50 rows=5 width=4) (actual time=0.33..0.71 rows=98 |
| loops=1) |
| Total runtime: 145.69 msec |
|
|
| EXPLAIN |
| bm221= |
|
|
|
|
| Here is the explain from the original database: |
|
|
| project= |
| psql:bad.qry:78: NOTICE: QUERY PLAN: |
|
|
| Sort (cost=337.23..337.23 rows=1 width=237) (actual time=14903.87..14904.05 |
| rows=181 loops=1) |
| -> Group (cost=337.19..337.22 rows=1 width=237) (actual |
| time=14895.90..14900.55 rows=181 loops=1) |
| -> Sort (cost=337.19..337.19 rows=1 width=237) (actual |
| time=14895.87..14896.09 rows=181 loops=1) |
| -> Nested Loop (cost=214.62..337.18 rows=1 width=237) |
| (actual time=149.50..14886.63 rows=181 loops=1) |
| -> Subquery Scan student_set (cost=208.82..208.84 |
| rows=1 width=115) (actual time=64.03..69.44 rows=181 loops=1) |
| -> Unique (cost=208.82..208.84 rows=1 width=115) |
| (actual time=64.02..67.25 rows=181 loops=1) |
| -> Sort (cost=208.82..208.82 rows=1 |
| width=115) (actual time=64.01..64.36 rows=181 loops=1) |
| -> Nested Loop (cost=16.54..208.81 |
| rows=1 width=115) (actual time=5.21..62.66 rows=181 loops=1) |
| -> Nested Loop |
| (cost=16.54..203.55 rows=1 width=88) (actual time=5.11..52.60 rows=181 |
| loops=1) |
| -> Hash Join |
| (cost=16.54..197.63 rows=1 width=64) (actual time=4.55..37.75 rows=181 |
| loops=1) |
| -> Seq Scan on |
| student_class_rlt scr (cost=0.00..178.16 rows=574 width=24) (actual |
| time=0.02..29.59 rows=527 loops=1) |
| -> Hash |
| (cost=16.54..16.54 rows=2 width=40) (actual time=3.84..3.84 rows=0 loops=1) |
| -> Hash Join |
| (cost=13.80..16.54 rows=2 width=40) (actual time=2.91..3.77 rows=27 loops=1) |
| -> Seq |
| Scan on bm_subscriptions_rlt bsr (cost=0.00..2.14 rows=114 width=8) (actual |
| time=0.01..0.50 rows=114 loops=1) |
| -> Hash |
| (cost=13.80..13.80 rows=2 width=32) (actual time=2.81..2.81 rows=0 loops=1) |
| -> |
| Hash Join (cost=1.06..13.80 rows=2 width=32) (actual time=1.74..2.78 |
| rows=11 loops=1) |
| |
| -> Seq Scan on bm_publications bp (cost=0.00..12.65 rows=11 width=12) |
| (actual time=1.56..2.51 rows=11 loops=1) |
| |
| -> Hash (cost=1.06..1.06 rows=1 width=20) (actual time=0.06..0.06 |
| rows=0 loops=1) |
| |
| -> Seq Scan on bm_publication_events bpe (cost=0.00..1.06 rows=1 |
| width=20) (actual time=0.04..0.05 rows=1 loops=1) |
| -> Index Scan using |
| user_common_pkey on user_common uc (cost=0.00..5.90 rows=1 width=24) |
| (actual time=0.05..0.06 rows=1 loops=181) |
| -> Index Scan using class_pkey |
| on classes c (cost=0.00..5.25 rows=1 width=27) (actual time=0.03..0.04 |
| rows=1 loops=181) |
| -> Subquery Scan participation_set (cost=5.79..109.63 |
| rows=1248 width=21) (actual time=1.19..78.18 rows=816 loops=181) |
| -> Hash Join (cost=5.79..109.63 rows=1248 |
| width=21) (actual time=1.18..71.10 rows=816 loops=181) |
| -> Seq Scan on bm_user_results bur |
| (cost=0.00..70.16 rows=3616 width=17) (actual time=0.01..20.96 rows=3620 |
| loops=181) |
| -> Hash (cost=5.55..5.55 rows=98 width=4) |
| (actual time=1.05..1.05 rows=0 loops=181) |
| -> Seq Scan on bm_publications bp |
| (cost=0.00..5.55 rows=98 width=4) (actual time=0.33..0.82 rows=98 loops=181) |
| Total runtime: 14905.87 msec |
|
|
| EXPLAIN |
| project= |
|
|
|
|
| Here is the query: |
|
|
| explain analyze |
| select |
| student_set.pub_id as pub_id, |
| student_set.class_id as class, |
| student_set.class_name as class_name, |
| student_set.user_id as student, |
| student_set.first_name, |
| student_set.last_name, |
| participation_set.started, |
| participation_set.complete, |
| day,month |
|
|
| from |
| ( |
|
|
| select distinct |
| scr.user_id, |
| scr.class_id, |
| uc.first_name, |
| uc.last_name, |
| bp.bm_publication_id as pub_id, |
| c.class_name |
| from student_class_rlt scr, |
| user_common uc, |
| bm_subscriptions_rlt bsr, |
| bm_publications bp CROSS JOIN |
| bm_publication_events bpe, |
| classes c |
| where |
| bpe.bm_publication_event_id = 4 |
| and bpe.bm_publication_event_id = |
| bp.bm_publication_event_id |
| and bp.bm_series_id = bsr.bm_series_id |
| and bsr.class_id = scr.class_id |
| and scr.class_id = c.class_id |
| and (scr.end_date is null or scr.end_date >= |
| bpe.due_date) |
| and scr.start_date <= bpe.publication_date |
| and scr.status_id != 2 |
| and scr.user_id = uc.user_id |
| and bp.bm_publication_id in ( |
| 4,25,1,3,26,19, |
| ,11,27,90,20,28 |
| ) |
|
|
| ) student_set |
| left join |
| ( |
|
|
| select user_id, |
| initial_timestmp as started, |
| to_char( initial_timestmp, 'MM/DD' ) as |
| day, |
| to_char( initial_timestmp, 'Month YYYY' ) |
| as month, |
| complete, |
| bur.bm_publication_id as pub_id |
| from |
| bm_publications bp, |
| bm_user_results bur |
| where |
| bp.bm_publication_event_id = 4 |
| and bp.bm_publication_id = bur.bm_publication_id |
|
|
|
|
| ) participation_set |
| on |
| ( |
| student_set.user_id = |
| participation_set.user_id |
| and student_set.pub_id = |
| participation_set.pub_id |
| ) |
| group by student_set.pub_id, class, class_name, student, |
| last_name, first_name, started, complete, day, month |
| order by student_set.pub_id, class, last_name, month, day |
|
|
| ; |
|
|
|
|
| Thanks. |
|
|
|
|
|
|
|
|
| > |
| > From: pgsql-performance-owner@postgresql.org |
| > [mailto:pgsql-performance-owner@postgresql.org]On Behalf Of Josh Berkus |
| > Sent: Monday, October 07, 2002 2:29 PM |
| > To: marie.tuite@edisonaffiliates.com; pgsql-performance@postgresql.org |
| > Subject: Re: [pgsql-performance] sloooow query |
| > |
| > |
| > |
| > Marie, |
| > |
| > > I am experiencing slow db performance. I have vacuumed, |
| > analyzed, reindexed |
| > > using the force option and performance remains the same - |
| > dog-slow :( If I |
| > > drop and recreate the database, performance is normal, so this |
| > suggests a |
| > > problem with the indexes? I also took a look at the |
| > postgresql.conf and all |
| > > appears fine. There are many instances of the same database running on |
| > > different servers and not all servers are experiencing the problem. |
| > |
| > Please post the following: |
| > 1) A copy of the relevant portions of your database schema. |
| > 2) The query that is running slowly. |
| > 3) The results of running EXPLAIN on that query. |
| > 4) Your PostgreSQL version and operating system |
| > 5) Any other relevant information about your databases, such as |
| > the quantity |
| > of inserts and deletes on the relevant tables. |
| > |
| > |
| > -Josh Berkus |
| > Aglio Database Solutions |
| > San Francisco |
| > |
| > |
| > |
| > TIP 5: Have you checked our extensive FAQ? |
| > |
| > http://www.postgresql.org/users-lounge/docs/faq.html |
| > |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 15:51:15 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id A80B04760D3; Mon, 7 Oct 2002 15:51:14 -0400 (EDT) |
| Received: from edisonaffiliates.com (w205.z208176060.chi-il.dsl.cnc.net |
| [208.176.60.205]) by postgresql.org (Postfix) with SMTP |
| id C08264760CE; Mon, 7 Oct 2002 15:51:13 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 14:46:27 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Justin Clift" <justin@postgresql.org>, <josh@agliodbs.com> |
| Cc: <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 14:53:35 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEEEBCCJAA.marie.tuite@edisonaffiliates.com> |
| MIME-Version: 1.0 |
| Content-Type: text/plain; |
| charset="US-ASCII" |
| Content-Transfer-Encoding: 7bit |
| X-Priority: 3 (Normal) |
| X-MSMail-Priority: Normal |
| X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) |
| In-Reply-To: <3DA1E0BB.236FCC17@postgresql.org> |
| Importance: Normal |
| X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/42 |
| X-Sequence-Number: 59 |
|
|
| Here is a show all: |
|
|
| Thanks, |
|
|
|
|
| project- |
| NOTICE: enable_seqscan is on |
| NOTICE: enable_indexscan is on |
| NOTICE: enable_tidscan is on |
| NOTICE: enable_sort is on |
| NOTICE: enable_nestloop is on |
| NOTICE: enable_mergejoin is on |
| NOTICE: enable_hashjoin is on |
| NOTICE: ksqo is off |
| NOTICE: geqo is on |
| NOTICE: tcpip_socket is on |
| NOTICE: ssl is off |
| NOTICE: fsync is on |
| NOTICE: silent_mode is off |
| NOTICE: log_connections is off |
| NOTICE: log_timestamp is off |
| NOTICE: log_pid is off |
| NOTICE: debug_print_query is off |
| NOTICE: debug_print_parse is off |
| NOTICE: debug_print_rewritten is off |
| NOTICE: debug_print_plan is off |
| NOTICE: debug_pretty_print is off |
| NOTICE: show_parser_stats is off |
| NOTICE: show_planner_stats is off |
| NOTICE: show_executor_stats is off |
| NOTICE: show_query_stats is off |
| NOTICE: stats_start_collector is on |
| NOTICE: stats_reset_on_server_start is on |
| NOTICE: stats_command_string is off |
| NOTICE: stats_row_level is off |
| NOTICE: stats_block_level is off |
| NOTICE: trace_notify is off |
| NOTICE: hostname_lookup is off |
| NOTICE: show_source_port is off |
| NOTICE: sql_inheritance is on |
| NOTICE: australian_timezones is off |
| NOTICE: fixbtree is on |
| NOTICE: password_encryption is off |
| NOTICE: transform_null_equals is off |
| NOTICE: geqo_threshold is 11 |
| NOTICE: geqo_pool_size is 0 |
| NOTICE: geqo_effort is 1 |
| NOTICE: geqo_generations is 0 |
| NOTICE: geqo_random_seed is -1 |
| NOTICE: deadlock_timeout is 1000 |
| NOTICE: syslog is 0 |
| NOTICE: max_connections is 64 |
| NOTICE: shared_buffers is 128 |
| NOTICE: port is 5432 |
| NOTICE: unix_socket_permissions is 511 |
| NOTICE: sort_mem is 1024 |
| NOTICE: vacuum_mem is 8192 |
| NOTICE: max_files_per_process is 1000 |
| NOTICE: debug_level is 0 |
| NOTICE: max_expr_depth is 10000 |
| NOTICE: max_fsm_relations is 100 |
| NOTICE: max_fsm_pages is 10000 |
| NOTICE: max_locks_per_transaction is 64 |
| NOTICE: authentication_timeout is 60 |
| NOTICE: pre_auth_delay is 0 |
| NOTICE: checkpoint_segments is 3 |
| NOTICE: checkpoint_timeout is 300 |
| NOTICE: wal_buffers is 8 |
| NOTICE: wal_files is 0 |
| NOTICE: wal_debug is 0 |
| NOTICE: commit_delay is 0 |
| NOTICE: commit_siblings is 5 |
| NOTICE: effective_cache_size is 1000 |
| NOTICE: random_page_cost is 4 |
| NOTICE: cpu_tuple_cost is 0.01 |
| NOTICE: cpu_index_tuple_cost is 0.001 |
| NOTICE: cpu_operator_cost is 0.0025 |
| NOTICE: geqo_selection_bias is 2 |
| NOTICE: default_transaction_isolation is read committed |
| NOTICE: dynamic_library_path is $libdir |
| NOTICE: krb_server_keyfile is FILE:/etc/pgsql/krb5.keytab |
| NOTICE: syslog_facility is LOCAL0 |
| NOTICE: syslog_ident is postgres |
| NOTICE: unix_socket_group is unset |
| NOTICE: unix_socket_directory is unset |
| NOTICE: virtual_host is unset |
| NOTICE: wal_sync_method is fdatasync |
| NOTICE: DateStyle is ISO with US (NonEuropean) conventions |
| NOTICE: Time zone is unset |
| NOTICE: TRANSACTION ISOLATION LEVEL is READ COMMITTED |
| NOTICE: Current client encoding is 'SQL_ASCII' |
| NOTICE: Current server encoding is 'SQL_ASCII' |
| NOTICE: Seed for random number generator is unavailable |
| SHOW VARIABLE |
| project= |
|
|
| > |
| > From: pgsql-performance-owner@postgresql.org |
| > [mailto:pgsql-performance-owner@postgresql.org]On Behalf Of Justin Clift |
| > Sent: Monday, October 07, 2002 2:30 PM |
| > To: josh@agliodbs.com |
| > Cc: marie.tuite@edisonaffiliates.com; pgsql-performance@postgresql.org |
| > Subject: Re: [pgsql-performance] sloooow query |
| > |
| > |
| > Josh Berkus wrote: |
| > > |
| > > Marie, |
| > > |
| > > > I am experiencing slow db performance. I have vacuumed, |
| > analyzed, reindexed |
| > > > using the force option and performance remains the same - |
| > dog-slow :( If I |
| > > > drop and recreate the database, performance is normal, so |
| > this suggests a |
| > > > problem with the indexes? I also took a look at the |
| > postgresql.conf and all |
| > > > appears fine. There are many instances of the same database |
| > running on |
| > > > different servers and not all servers are experiencing the problem. |
| > > |
| > > Please post the following: |
| > > 1) A copy of the relevant portions of your database schema. |
| > > 2) The query that is running slowly. |
| > > 3) The results of running EXPLAIN on that query. |
| > > 4) Your PostgreSQL version and operating system |
| > > 5) Any other relevant information about your databases, such as |
| > the quantity |
| > > of inserts and deletes on the relevant tables. |
| > |
| > 6) And the sort_mem, shared_buffers, vacuum_mem, wal_buffers, and |
| > wal_files settings from your postgresql.conf file, if possible. |
| > |
| > :-) |
| > |
| > Regards and best wishes, |
| > |
| > Justin Clift |
| > |
| > |
| > > |
| > > -Josh Berkus |
| > > Aglio Database Solutions |
| > > San Francisco |
| > > |
| > > |
| > > TIP 5: Have you checked our extensive FAQ? |
| > > |
| > > http://www.postgresql.org/users-lounge/docs/faq.html |
| > |
| > |
| > "My grandfather once told me that there are two kinds of people: those |
| > who work and those who take the credit. He told me to try to be in the |
| > first group; there was less competition there." |
| > - Indira Gandhi |
| > |
| > |
| > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org |
| > |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:10:01 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id EB42C476807 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:09:59 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id A204B476709 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:09:53 -0400 (EDT) |
| Received: from [66.219.92.2] (HELO chocolate-mousse) |
| by davinci.ethosmedia.com (CommuniGate Pro SMTP 3.5.9) |
| with ESMTP id 1774389; Mon, 07 Oct 2002 13:08:27 -0700 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Reply-To: josh@agliodbs.com |
| Organization: Aglio Database Solutions |
| To: <marie.tuite@edisonaffiliates.com>, |
| <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 13:12:21 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <IGELKLINGDMODABPOOFEMEBBCJAA.marie.tuite@edisonaffiliates.com> |
| In-Reply-To: <IGELKLINGDMODABPOOFEMEBBCJAA.marie.tuite@edisonaffiliates.com> |
| MIME-Version: 1.0 |
| Content-Transfer-Encoding: quoted-printable |
| Message-Id: <200210071312.21476.josh@agliodbs.com> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/43 |
| X-Sequence-Number: 60 |
|
|
|
|
| Marie, |
|
|
| > I pg_dumped the first database having performance problems and reloaded it |
| > into a new database on the same server. The query ran normally when I |
| > reloaded it. There is no difference in hardware, schema or anything else. |
|
|
| That's a pretty brutal query.=20=20 |
| |
| From the comparison between the two queries, it looks like you have a lot o= |
| f=20 |
| discarded rows cluttering up the original database, just like I did.=20=20 |
| |
| What happens if you run VACUUM FULL VERBOSE on the Bad database? Does it= |
| =20 |
| report lots of rows taken up? |
| |
| --=20 |
| -Josh Berkus |
| |
| ______AGLIO DATABASE SOLUTIONS___________________________ |
| Josh Berkus |
| Complete information technology josh@agliodbs.com |
| and data management solutions (415) 565-7293 |
| for law firms, small businesses fax 621-2533 |
| and non-profit organizations. San Francisco |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:15:39 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 2771F4763F5 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:15:39 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 02D32476237 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:15:38 -0400 (EDT) |
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| Message-ID: <3DA1EB67.7D717CB0@postgresql.org> |
| Date: Tue, 08 Oct 2002 06:15:35 +1000 |
| From: Justin Clift <justin@postgresql.org> |
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| To: marie.tuite@edisonaffiliates.com |
| Cc: josh@agliodbs.com, pgsql-performance@postgresql.org |
| Subject: Re: sloooow query |
| References: <IGELKLINGDMODABPOOFEEEBCCJAA.marie.tuite@edisonaffiliates.com> |
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| |
| Hi Marie, |
| |
| Ok, not sure about the SQL side of things (got scared just *looking* at |
| that query), but if this is at least a mostly-dedicated database server |
| then you might want to bump up some of those buffer values. They look |
| like defaults (except the max_connections and shared buffers). |
| |
| Initial thought is making just sort_mem = 8192 or so as a minimum (it |
| could go a lot higher, but not sure of your memory configuration), as |
| see if that makes a difference. |
| |
| Not sure the wal_files = 0 bit is good either. Haven't seen that set to |
| 0 before. |
|
|
| Might not assist with your present crisis, but am guessing PostgreSQL is |
| chewing a lot of CPU and being slow in general with the present |
| settings. |
|
|
| :-) |
|
|
| Regards and best wishes, |
|
|
| Justin Clift |
|
|
|
|
| "Marie G. Tuite" wrote: |
| > |
| > Here is a show all: |
| > |
| > Thanks, |
| > |
| > project- |
| > NOTICE: enable_seqscan is on |
| > NOTICE: enable_indexscan is on |
| > NOTICE: enable_tidscan is on |
| > NOTICE: enable_sort is on |
| > NOTICE: enable_nestloop is on |
| > NOTICE: enable_mergejoin is on |
| > NOTICE: enable_hashjoin is on |
| > NOTICE: ksqo is off |
| > NOTICE: geqo is on |
| > NOTICE: tcpip_socket is on |
| > NOTICE: ssl is off |
| > NOTICE: fsync is on |
| > NOTICE: silent_mode is off |
| > NOTICE: log_connections is off |
| > NOTICE: log_timestamp is off |
| > NOTICE: log_pid is off |
| > NOTICE: debug_print_query is off |
| > NOTICE: debug_print_parse is off |
| > NOTICE: debug_print_rewritten is off |
| > NOTICE: debug_print_plan is off |
| > NOTICE: debug_pretty_print is off |
| > NOTICE: show_parser_stats is off |
| > NOTICE: show_planner_stats is off |
| > NOTICE: show_executor_stats is off |
| > NOTICE: show_query_stats is off |
| > NOTICE: stats_start_collector is on |
| > NOTICE: stats_reset_on_server_start is on |
| > NOTICE: stats_command_string is off |
| > NOTICE: stats_row_level is off |
| > NOTICE: stats_block_level is off |
| > NOTICE: trace_notify is off |
| > NOTICE: hostname_lookup is off |
| > NOTICE: show_source_port is off |
| > NOTICE: sql_inheritance is on |
| > NOTICE: australian_timezones is off |
| > NOTICE: fixbtree is on |
| > NOTICE: password_encryption is off |
| > NOTICE: transform_null_equals is off |
| > NOTICE: geqo_threshold is 11 |
| > NOTICE: geqo_pool_size is 0 |
| > NOTICE: geqo_effort is 1 |
| > NOTICE: geqo_generations is 0 |
| > NOTICE: geqo_random_seed is -1 |
| > NOTICE: deadlock_timeout is 1000 |
| > NOTICE: syslog is 0 |
| > NOTICE: max_connections is 64 |
| > NOTICE: shared_buffers is 128 |
| > NOTICE: port is 5432 |
| > NOTICE: unix_socket_permissions is 511 |
| > NOTICE: sort_mem is 1024 |
| > NOTICE: vacuum_mem is 8192 |
| > NOTICE: max_files_per_process is 1000 |
| > NOTICE: debug_level is 0 |
| > NOTICE: max_expr_depth is 10000 |
| > NOTICE: max_fsm_relations is 100 |
| > NOTICE: max_fsm_pages is 10000 |
| > NOTICE: max_locks_per_transaction is 64 |
| > NOTICE: authentication_timeout is 60 |
| > NOTICE: pre_auth_delay is 0 |
| > NOTICE: checkpoint_segments is 3 |
| > NOTICE: checkpoint_timeout is 300 |
| > NOTICE: wal_buffers is 8 |
| > NOTICE: wal_files is 0 |
| > NOTICE: wal_debug is 0 |
| > NOTICE: commit_delay is 0 |
| > NOTICE: commit_siblings is 5 |
| > NOTICE: effective_cache_size is 1000 |
| > NOTICE: random_page_cost is 4 |
| > NOTICE: cpu_tuple_cost is 0.01 |
| > NOTICE: cpu_index_tuple_cost is 0.001 |
| > NOTICE: cpu_operator_cost is 0.0025 |
| > NOTICE: geqo_selection_bias is 2 |
| > NOTICE: default_transaction_isolation is read committed |
| > NOTICE: dynamic_library_path is $libdir |
| > NOTICE: krb_server_keyfile is FILE:/etc/pgsql/krb5.keytab |
| > NOTICE: syslog_facility is LOCAL0 |
| > NOTICE: syslog_ident is postgres |
| > NOTICE: unix_socket_group is unset |
| > NOTICE: unix_socket_directory is unset |
| > NOTICE: virtual_host is unset |
| > NOTICE: wal_sync_method is fdatasync |
| > NOTICE: DateStyle is ISO with US (NonEuropean) conventions |
| > NOTICE: Time zone is unset |
| > NOTICE: TRANSACTION ISOLATION LEVEL is READ COMMITTED |
| > NOTICE: Current client encoding is 'SQL_ASCII' |
| > NOTICE: Current server encoding is 'SQL_ASCII' |
| > NOTICE: Seed for random number generator is unavailable |
| > SHOW VARIABLE |
| > project= |
| > |
| > > |
| > > From: pgsql-performance-owner@postgresql.org |
| > > [mailto:pgsql-performance-owner@postgresql.org]On Behalf Of Justin Clift |
| > > Sent: Monday, October 07, 2002 2:30 PM |
| > > To: josh@agliodbs.com |
| > > Cc: marie.tuite@edisonaffiliates.com; pgsql-performance@postgresql.org |
| > > Subject: Re: [pgsql-performance] sloooow query |
| > > |
| > > |
| > > Josh Berkus wrote: |
| > > > |
| > > > Marie, |
| > > > |
| > > > > I am experiencing slow db performance. I have vacuumed, |
| > > analyzed, reindexed |
| > > > > using the force option and performance remains the same - |
| > > dog-slow :( If I |
| > > > > drop and recreate the database, performance is normal, so |
| > > this suggests a |
| > > > > problem with the indexes? I also took a look at the |
| > > postgresql.conf and all |
| > > > > appears fine. There are many instances of the same database |
| > > running on |
| > > > > different servers and not all servers are experiencing the problem. |
| > > > |
| > > > Please post the following: |
| > > > 1) A copy of the relevant portions of your database schema. |
| > > > 2) The query that is running slowly. |
| > > > 3) The results of running EXPLAIN on that query. |
| > > > 4) Your PostgreSQL version and operating system |
| > > > 5) Any other relevant information about your databases, such as |
| > > the quantity |
| > > > of inserts and deletes on the relevant tables. |
| > > |
| > > 6) And the sort_mem, shared_buffers, vacuum_mem, wal_buffers, and |
| > > wal_files settings from your postgresql.conf file, if possible. |
| > > |
| > > :-) |
| > > |
| > > Regards and best wishes, |
| > > |
| > > Justin Clift |
| > > |
| > > |
| > > > |
| > > > -Josh Berkus |
| > > > Aglio Database Solutions |
| > > > San Francisco |
| > > > |
| > > > |
| > > > TIP 5: Have you checked our extensive FAQ? |
| > > > |
| > > > http://www.postgresql.org/users-lounge/docs/faq.html |
| > > |
| > > |
| > > "My grandfather once told me that there are two kinds of people: those |
| > > who work and those who take the credit. He told me to try to be in the |
| > > first group; there was less competition there." |
| > > - Indira Gandhi |
| > > |
| > > |
| > > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org |
| > > |
|
|
| |
| "My grandfather once told me that there are two kinds of people: those |
| who work and those who take the credit. He told me to try to be in the |
| first group; there was less competition there." |
| - Indira Gandhi |
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:32:08 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 179F4475F66 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:32:08 -0400 (EDT) |
| Received: from edisonaffiliates.com (w205.z208176060.chi-il.dsl.cnc.net |
| [208.176.60.205]) |
| by postgresql.org (Postfix) with SMTP id 00576476823 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:31:52 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 15:27:03 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 15:34:11 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFECEBECJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| > What happens if you run VACUUM FULL VERBOSE on the Bad database? Does it |
| > report lots of rows taken up? |
|
|
| I ran the vacuum for selected tables. It looks fine, I think, but I amn't |
| always sure what I am reading in output. |
| |
| project=# vacuum full verbose classes; |
| NOTICE: --Relation classes-- |
| NOTICE: Pages 5: Changed 0, reaped 2, Empty 0, New 0; Tup 332: Vac 0, |
| Keep/VTL 0/0, UnUsed 33, MinLen 93, MaxLen 117; Re-using: Free/Avail. Space |
| 3020/2832; EndEmpty/Avail. Pages 0/1. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index class_pkey: Pages 5; Tuples 332: Deleted 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Rel classes: Pages: 5 --> 5; Tuple(s) moved: 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: --Relation pg_toast_595650-- |
| NOTICE: Pages 0: Changed 0, reaped 0, Empty 0, New 0; Tup 0: Vac 0, |
| Keep/VTL 0/0, UnUsed 0, MinLen 0, MaxLen 0; Re-using: Free/Avail. Space 0/0; |
| EndEmpty/Avail. Pages 0/0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index pg_toast_595650_idx: Pages 1; Tuples 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| VACUUM |
| project=# vacuum full verbose bm_publications; |
| NOTICE: --Relation bm_publications-- |
| NOTICE: Pages 2: Changed 0, reaped 1, Empty 0, New 0; Tup 284: Vac 0, |
| Keep/VTL 0/0, UnUsed 6, MinLen 52, MaxLen 52; Re-using: Free/Avail. Space |
| 416/416; EndEmpty/Avail. Pages 0/2. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index bm_publications_pkey: Pages 4; Tuples 284: Deleted 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Rel bm_publications: Pages: 2 --> 2; Tuple(s) moved: 0. |
| CPU 0.00s/0.01u sec elapsed 0.00 sec. |
| VACUUM |
| project=# vacuum full verbose user_common; |
| NOTICE: --Relation user_common-- |
| NOTICE: Pages 21: Changed 0, reaped 19, Empty 0, New 0; Tup 1045: Vac 0, |
| Keep/VTL 0/0, UnUsed 103, MinLen 117, MaxLen 221; Re-using: Free/Avail. |
| Space 4080/2968; EndEmpty/Avail. Pages 0/2. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index user_common_pkey: Pages 20; Tuples 1045: Deleted 0. |
| CPU 0.01s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Rel user_common: Pages: 21 --> 21; Tuple(s) moved: 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: --Relation pg_toast_474892-- |
| NOTICE: Pages 0: Changed 0, reaped 0, Empty 0, New 0; Tup 0: Vac 0, |
| Keep/VTL 0/0, UnUsed 0, MinLen 0, MaxLen 0; Re-using: Free/Avail. Space 0/0; |
| EndEmpty/Avail. Pages 0/0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index pg_toast_474892_idx: Pages 1; Tuples 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| VACUUM |
| project=# vacuum full verbose bm_subscriptions_rlt; |
| NOTICE: --Relation bm_subscriptions_rlt-- |
| NOTICE: Pages 1: Changed 0, reaped 1, Empty 0, New 0; Tup 114: Vac 0, |
| Keep/VTL 0/0, UnUsed 1, MinLen 57, MaxLen 57; Re-using: Free/Avail. Space |
| 872/872; EndEmpty/Avail. Pages 0/1. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Index bm_subscriptions_rlt_pkey: Pages 2; Tuples 114: Deleted 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| NOTICE: Rel bm_subscriptions_rlt: Pages: 1 --> 1; Tuple(s) moved: 0. |
| CPU 0.00s/0.00u sec elapsed 0.00 sec. |
| VACUUM |
| project=# |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:42:05 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id E4AFE476856 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:42:03 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id EE2E64767C5 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:42:02 -0400 (EDT) |
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| with ESMTP id 1774449; Mon, 07 Oct 2002 13:40:37 -0700 |
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| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Reply-To: josh@agliodbs.com |
| Organization: Aglio Database Solutions |
| To: <marie.tuite@edisonaffiliates.com>, |
| <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 13:44:31 -0700 |
| X-Mailer: KMail [version 1.4] |
| References: <IGELKLINGDMODABPOOFECEBECJAA.marie.tuite@edisonaffiliates.com> |
| In-Reply-To: <IGELKLINGDMODABPOOFECEBECJAA.marie.tuite@edisonaffiliates.com> |
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| |
| |
| Marie, |
| |
| > I ran the vacuum for selected tables. It looks fine, I think, but I amn't |
| > always sure what I am reading in output. |
|
|
| So much for the easy answer. The reason I wanted to see a VACUUM FULL is= |
| =20 |
| that the query on the "bad" database is taking a long time to return even t= |
| he=20 |
| first row of many of its sub-parts. This is usually the result of not=20 |
| running VACUUM FULL after a lot of deletions. |
|
|
| However, your problem apparently is something else. Is is possible that= |
| =20 |
| there is some kind of disk access problem for the bad database copy? Is=20 |
| there a difference in where its files are physically located? |
|
|
|
|
| |
| -Josh Berkus |
| Aglio Database Solutions |
| San Francisco |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:54:57 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 8BB3D476352; Mon, 7 Oct 2002 16:54:54 -0400 (EDT) |
| Received: from briar.mmrd.com (unknown [208.255.226.182]) |
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| id TK2FXNDK; Mon, 7 Oct 2002 16:54:51 -0400 |
| Subject: Re: sloooow query |
| From: Robert Treat <xzilla@users.sourceforge.net> |
| To: Justin Clift <justin@postgresql.org> |
| Cc: marie.tuite@edisonaffiliates.com, josh@agliodbs.com, |
| pgsql-performance@postgresql.org |
| In-Reply-To: <3DA1EB67.7D717CB0@postgresql.org> |
| References: <IGELKLINGDMODABPOOFEEEBCCJAA.marie.tuite@edisonaffiliates.com> |
| <3DA1EB67.7D717CB0@postgresql.org> |
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| Date: 07 Oct 2002 16:50:27 -0400 |
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| X-Archive-Number: 200210/47 |
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|
|
| On Mon, 2002-10-07 at 16:15, Justin Clift wrote: |
| > Hi Marie, |
| > |
| > Not sure the wal_files = 0 bit is good either. Haven't seen that set to |
| > 0 before. |
| > |
| |
| This is the default value, and I don't recall anything in the docs that |
| would suggest to change it. Also IIRC the back end will auto adjust the |
| |
| like "DEBUG: XLogWrite: new log file created - consider increasing |
| WAL_FILES" I think you can leave this alone. Can you point me to |
| something that says different? |
|
|
| Robert Treat |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:56:45 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 16:56:44 -0400 (EDT) |
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| id TK2FXNDX; Mon, 7 Oct 2002 16:56:41 -0400 |
| Subject: Re: sloooow query |
| From: Robert Treat <xzilla@users.sourceforge.net> |
| To: marie.tuite@edisonaffiliates.com |
| Cc: josh@agliodbs.com, pgsql-performance@postgresql.org |
| In-Reply-To: <IGELKLINGDMODABPOOFECEBECJAA.marie.tuite@edisonaffiliates.com> |
| References: <IGELKLINGDMODABPOOFECEBECJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| On Mon, 2002-10-07 at 16:34, Marie G. Tuite wrote: |
| > > What happens if you run VACUUM FULL VERBOSE on the Bad database? Does it |
| > > report lots of rows taken up? |
| > |
| > I ran the vacuum for selected tables. It looks fine, I think, but I amn't |
| > always sure what I am reading in output. |
| > |
| |
| Is this vacuum being done on a system that is currently running slow, or |
| was this system recently dropped/reloaded? |
| |
| Robert Treat |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 7 16:57:49 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 3FA7D476955 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:57:49 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 5E11647694A |
| for <pgsql-performance@postgresql.org>; |
| Mon, 7 Oct 2002 16:57:48 -0400 (EDT) |
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| Mon, 7 Oct 2002 16:57:40 -0400 (EDT) |
| To: marie.tuite@edisonaffiliates.com |
| Cc: josh@agliodbs.com, pgsql-performance@postgresql.org |
| Subject: Re: sloooow query |
| In-reply-to: <IGELKLINGDMODABPOOFEMEBBCJAA.marie.tuite@edisonaffiliates.com> |
| References: <IGELKLINGDMODABPOOFEMEBBCJAA.marie.tuite@edisonaffiliates.com> |
| Comments: In-reply-to "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| message dated "Mon, 07 Oct 2002 14:49:16 -0500" |
| Date: Mon, 07 Oct 2002 16:57:40 -0400 |
| Message-ID: <26239.1034024260@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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| |
| "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> writes: |
| > I pg_dumped the first database having performance problems and reloaded it |
| > into a new database on the same server. The query ran normally when I |
| > reloaded it. There is no difference in hardware, schema or anything else. |
| |
| Have you done an ANALYZE or VACUUM ANALYZE in either database? The |
| statistics the planner is working from seem to be quite different |
| in the two plans. |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 7 17:01:02 2002 |
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| Message-ID: <3DA1F609.B2570F2F@postgresql.org> |
| Date: Tue, 08 Oct 2002 07:00:57 +1000 |
| From: Justin Clift <justin@postgresql.org> |
| X-Mailer: Mozilla 4.79 [en] (WinNT; U) |
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| MIME-Version: 1.0 |
| To: Robert Treat <xzilla@users.sourceforge.net> |
| Cc: marie.tuite@edisonaffiliates.com, josh@agliodbs.com, |
| pgsql-performance@postgresql.org |
| Subject: Re: sloooow query |
| References: <IGELKLINGDMODABPOOFEEEBCCJAA.marie.tuite@edisonaffiliates.com> |
| <3DA1EB67.7D717CB0@postgresql.org> <1034023827.3539.99.camel@camel> |
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| |
| Robert Treat wrote: |
| > |
| > On Mon, 2002-10-07 at 16:15, Justin Clift wrote: |
| > > Hi Marie, |
| > > |
| > > Not sure the wal_files = 0 bit is good either. Haven't seen that set to |
| > > 0 before. |
| > > |
| > |
| > This is the default value, and I don't recall anything in the docs that |
| > would suggest to change it. Also IIRC the back end will auto adjust the |
| > # of wal_files as needed in newer versions. Unless your seeing messages |
| > like "DEBUG: XLogWrite: new log file created - consider increasing |
| > WAL_FILES" I think you can leave this alone. Can you point me to |
| > something that says different? |
| |
| Ahh... that makes sense. Have been doing almost nothing else recently |
| except for setting up new PostgreSQL databases, loading in data, then |
| doing load testing for things. |
| |
| Have totally become so used to having wal_files being other than 0 that |
| it didn't even register that this is the default. ;-> |
|
|
| Sorry about that, and thanks for the heads up. |
|
|
| :-) |
|
|
| Regards and best wishes, |
|
|
| Justin Clift |
|
|
|
|
| > Robert Treat |
|
|
| |
| "My grandfather once told me that there are two kinds of people: those |
| who work and those who take the credit. He told me to try to be in the |
| first group; there was less competition there." |
| - Indira Gandhi |
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 18:01:52 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 18:01:50 -0400 (EDT) |
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| Mon, 7 Oct 2002 18:01:47 -0400 (EDT) |
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| Mon, 07 Oct 2002 16:57:01 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Tom Lane" <tgl@sss.pgh.pa.us> |
| Cc: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 17:04:09 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEMEBHCJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| I have analyzed, vacuumed and reindexed. |
|
|
| > |
| > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] |
| > Sent: Monday, October 07, 2002 3:58 PM |
| > To: marie.tuite@edisonaffiliates.com |
| > Cc: josh@agliodbs.com; pgsql-performance@postgresql.org |
| > Subject: Re: [pgsql-performance] sloooow query |
| > |
| > |
| > "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> writes: |
| > > I pg_dumped the first database having performance problems and |
| > reloaded it |
| > > into a new database on the same server. The query ran normally when I |
| > > reloaded it. There is no difference in hardware, schema or |
| > anything else. |
| > |
| > Have you done an ANALYZE or VACUUM ANALYZE in either database? The |
| > statistics the planner is working from seem to be quite different |
| > in the two plans. |
| > |
| > regards, tom lane |
| > |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 18:03:49 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 18:03:49 -0400 (EDT) |
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| Mon, 7 Oct 2002 18:03:48 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 16:57:01 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Robert Treat" <xzilla@users.sourceforge.net> |
| Cc: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 17:04:09 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEIEBHCJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| > Is this vacuum being done on a system that is currently running slow, or |
| > was this system recently dropped/reloaded? |
|
|
| Currently slow. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 18:03:22 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 18:03:22 -0400 (EDT) |
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| Mon, 7 Oct 2002 18:03:21 -0400 (EDT) |
| Received: from redhen ([12.32.94.66]) by edisonaffiliates.com ; |
| Mon, 07 Oct 2002 16:58:36 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 17:05:41 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEGEBICJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| > However, your problem apparently is something else. Is is possible that |
| > there is some kind of disk access problem for the bad database copy? Is |
| > there a difference in where its files are physically located? |
|
|
| Both are in default storage - /var/lib/pgsql/data. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 18:07:28 2002 |
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| Mon, 7 Oct 2002 18:07:26 -0400 (EDT) |
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| Mon, 07 Oct 2002 17:02:38 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Robert Treat" <xzilla@users.sourceforge.net> |
| Cc: <josh@agliodbs.com>, <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 17:09:46 -0500 |
| Message-ID: <IGELKLINGDMODABPOOFEOEBICJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| > Is this vacuum being done on a system that is currently running slow, or |
| > was this system recently dropped/reloaded? |
|
|
| Currently slow. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 7 18:10:25 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Mon, 7 Oct 2002 18:10:24 -0400 (EDT) |
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| Mon, 07 Oct 2002 17:05:33 -0500 |
| Reply-To: <marie.tuite@edisonaffiliates.com> |
| From: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| To: "Pgsql-Performance@Postgresql. Org" <pgsql-performance@postgresql.org> |
| Subject: Re: sloooow query |
| Date: Mon, 7 Oct 2002 17:12:41 -0500 |
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|
|
|
|
| > Have you done an ANALYZE or VACUUM ANALYZE in either database? The |
| > statistics the planner is working from seem to be quite different |
| > in the two plans. |
|
|
| I have vacuumed, analysed and reindexed. |
|
|
|
|
|
|
| From pgsql-general-owner@postgresql.org Mon Oct 7 20:03:23 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 9AF96475E77; Mon, 7 Oct 2002 20:03:22 -0400 (EDT) |
| Received: from svana.org (t1-1-076.dialup.apex.net.au [203.20.62.76]) |
| by postgresql.org (Postfix) with ESMTP |
| id BF37D475DAD; Mon, 7 Oct 2002 20:03:20 -0400 (EDT) |
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| id 17yhq8-0007cg-00; Tue, 08 Oct 2002 10:03:08 +1000 |
| Date: Tue, 8 Oct 2002 10:03:08 +1000 |
| From: Martijn van Oosterhout <kleptog@svana.org> |
| To: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com> |
| Cc: "Pgsql-General@Postgresql. Org" <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: sloooow query |
| Message-ID: <20021008000308.GA28930@svana.org> |
| Reply-To: Martijn van Oosterhout <kleptog@svana.org> |
| Mail-Followup-To: "Marie G. Tuite" <marie.tuite@edisonaffiliates.com>, |
| "Pgsql-General@Postgresql. Org" <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| References: <IGELKLINGDMODABPOOFEKEAPCJAA.marie.tuite@edisonaffiliates.com> |
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|
|
| On Mon, Oct 07, 2002 at 02:22:09PM -0500, Marie G. Tuite wrote: |
| > Hello all, |
| > |
| > I am experiencing slow db performance. I have vacuumed, analyzed, reindexed |
| > using the force option and performance remains the same - dog-slow :( If I |
| > drop and recreate the database, performance is normal, so this suggests a |
| > problem with the indexes? I also took a look at the postgresql.conf and all |
| > appears fine. There are many instances of the same database running on |
| > different servers and not all servers are experiencing the problem. |
|
|
| We need more details if you wish to receive useful answers. Query/EXPLAIN |
| output/schema, etc |
|
|
| |
| Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ |
| > There are 10 kinds of people in the world, those that can do binary |
| > arithmetic and those that can't. |
| |
| From pgsql-general-owner@postgresql.org Tue Oct 8 01:43:47 2002 |
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| Tue, 8 Oct 2002 01:43:46 -0400 (EDT) |
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| Tue, 8 Oct 2002 11:15:16 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Tue, 08 Oct 2002 11:14:11 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [pgsql-performance] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA2BE03.3674.13CF7DD1@localhost> |
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| |
| On 7 Oct 2002 at 11:21, Tom Lane wrote: |
| |
| > "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > > I say if it's a char field, there should be no indicator of length as |
| > > it's not required. Just store those many characters straight ahead.. |
| > |
| > Your assumption fails when considering UNICODE or other multibyte |
| > character encodings. |
| |
| Correct but is it possible to have real char string when database is not |
| unicode or when locale defines size of char, to be exact? |
| |
| In my case varchar does not make sense as all strings are guaranteed to be of |
| defined length. While the argument you have put is correct, it's causing a disk |
| space leak, to say so. |
|
|
| Bye |
| Shridhar |
|
|
| |
| Boucher's Observation: He who blows his own horn always plays the music several |
| octaves higher than originally written. |
| |
| |
| From pgsql-general-owner@postgresql.org Tue Oct 8 03:21:04 2002 |
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| Date: Tue, 8 Oct 2002 17:20:47 +1000 |
| From: Martijn van Oosterhout <kleptog@svana.org> |
| To: Shridhar Daithankar <shridhar_daithankar@persistent.co.in> |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| Message-ID: <20021008072047.GB558@svana.org> |
| Reply-To: Martijn van Oosterhout <kleptog@svana.org> |
| Mail-Followup-To: Shridhar Daithankar <shridhar_daithankar@persistent.co.in>, |
| pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
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| |
| On Tue, Oct 08, 2002 at 11:14:11AM +0530, Shridhar Daithankar wrote: |
| > On 7 Oct 2002 at 11:21, Tom Lane wrote: |
| > |
| > > "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > > > I say if it's a char field, there should be no indicator of length as |
| > > > it's not required. Just store those many characters straight ahead.. |
| > > |
| > > Your assumption fails when considering UNICODE or other multibyte |
| > > character encodings. |
| > |
| > Correct but is it possible to have real char string when database is not |
| > unicode or when locale defines size of char, to be exact? |
| > |
| > In my case varchar does not make sense as all strings are guaranteed to be of |
| > defined length. While the argument you have put is correct, it's causing a disk |
| > space leak, to say so. |
|
|
| Well, maybe. But since 7.1 or so char() and varchar() simply became text |
| with some length restrictions. This was one of the reasons. It also |
| simplified a lot of code. |
| |
| Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ |
| > There are 10 kinds of people in the world, those that can do binary |
| > arithmetic and those that can't. |
| |
| From pgsql-general-owner@postgresql.org Tue Oct 8 09:33:56 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 34D0C476993 |
| for <pgsql-general@postgresql.org>; |
| Tue, 8 Oct 2002 09:33:54 -0400 (EDT) |
| Received: from smtp014.mail.yahoo.com (smtp014.mail.yahoo.com |
| [216.136.173.58]) |
| by postgresql.org (Postfix) with SMTP id 69EC3476117 |
| for <pgsql-general@postgresql.org>; |
| Tue, 8 Oct 2002 09:33:03 -0400 (EDT) |
| Received: from psc.progress.com (HELO Yahoo.com) (janwieck@192.233.92.200 with |
| plain) |
| by smtp.mail.vip.sc5.yahoo.com with SMTP; 8 Oct 2002 13:32:55 -0000 |
| Message-ID: <3DA2DE82.1AC84934@Yahoo.com> |
| Date: Tue, 08 Oct 2002 09:32:50 -0400 |
| From: Jan Wieck <JanWieck@Yahoo.com> |
| Organization: Home |
| X-Mailer: Mozilla 4.79 [en] (Windows NT 5.0; U) |
| X-Accept-Language: en,ru |
| MIME-Version: 1.0 |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Cc: David Blood <david@matraex.com>, pgsql-general@postgresql.org |
| Subject: Re: Pinning a table into memory |
| References: <03a301c26bc5$a799a970$1f00a8c0@redwood> |
| <25545.1033757267@sss.pgh.pa.us> |
| Content-Type: text/plain; charset=us-ascii |
| Content-Transfer-Encoding: 7bit |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/445 |
| X-Sequence-Number: 31443 |
| |
| Tom Lane wrote: |
| > |
| > "David Blood" <david@matraex.com> writes: |
| > > In Oracle you can Pin large objects into memory to prevent frequent |
| > > reloads. Is there anyway to do this with Postgres? |
| > |
| > I can never understand why people think this would be a good idea. |
| > If you're hitting a table frequently, it will stay in memory anyway |
| > (either in Postgres shared buffers or kernel disk cache). If you're |
| > not hitting it frequently enough to keep it swapped in, then whatever |
| > is getting swapped in instead is probably a better candidate to be |
| > occupying the space. |
| |
| As I understand it, he's looking for a mechanism to prevent a single |
| sequential scan on a table, larger than the buffer cache, to kick out |
| everything else at once. But I agree with you that pinning other objects |
| is just mucking with the symptoms instead of curing the desease. |
|
|
|
|
| Jan |
|
|
| |
|
|
| |
| |
| |
| |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 8 09:53:18 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 2575C476E64 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 09:53:16 -0400 (EDT) |
| Received: from lakemtao04.cox.net (lakemtao04.cox.net [68.1.17.241]) |
| by postgresql.org (Postfix) with ESMTP id 1078747651A |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 09:51:07 -0400 (EDT) |
| Received: from localhost.localdomain ([68.11.66.83]) by lakemtao04.cox.net |
| (InterMail vM.5.01.04.05 201-253-122-122-105-20011231) with ESMTP |
| id <20021008135106.FWLY1315.lakemtao04.cox.net@localhost.localdomain> |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 09:51:06 -0400 |
| Subject: Re: [GENERAL] Large databases, performance |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <20021008072047.GB558@svana.org> |
| References: <3DA1E50F.4394.107FF85D@localhost> |
| <3DA2BE03.3674.13CF7DD1@localhost> <20021008072047.GB558@svana.org> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
| X-Mailer: Ximian Evolution 1.0.8 |
| Date: 08 Oct 2002 08:50:52 -0500 |
| Message-Id: <1034085052.1094.14.camel@haggis> |
| Mime-Version: 1.0 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/59 |
| X-Sequence-Number: 76 |
|
|
| On Tue, 2002-10-08 at 02:20, Martijn van Oosterhout wrote: |
| > On Tue, Oct 08, 2002 at 11:14:11AM +0530, Shridhar Daithankar wrote: |
| > > On 7 Oct 2002 at 11:21, Tom Lane wrote: |
| > > |
| > > > "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes: |
| > > > > I say if it's a char field, there should be no indicator of length as |
| > > > > it's not required. Just store those many characters straight ahead.. |
| > > > |
| > > > Your assumption fails when considering UNICODE or other multibyte |
| > > > character encodings. |
| > > |
| > > Correct but is it possible to have real char string when database is not |
| > > unicode or when locale defines size of char, to be exact? |
| > > |
| > > In my case varchar does not make sense as all strings are guaranteed to be of |
| > > defined length. While the argument you have put is correct, it's causing a disk |
| > > space leak, to say so. |
| |
| Not only that, but you get INSERT, UPDATE, DELETE and SELECT performance |
| gains with fixed length records, since you don't get fragmentation. |
|
|
| For example: |
| TABLE T |
| F1 INTEGER; |
| F2 VARCHAR(200) |
|
|
| INSERT INTO T VALUES (1, 'FOO BAR'); |
| INSERT INTO T VALUES (2, 'SNAFU'); |
|
|
| Next, |
| UPDATE T SET F2 = 'WIGGLE WAGGLE WUMPERSTUMPER' WHERE F1 = 1; |
|
|
| Unless there is a big gap on disk between the 2 inserted records, |
| postgresql must then look somewhere else for space to put the new |
| version of T WHERE F1 = 1. |
|
|
| With fixed-length records, you know exactly where you can put the |
| new value of F2, thus minimizing IO. |
|
|
| > Well, maybe. But since 7.1 or so char() and varchar() simply became text |
| > with some length restrictions. This was one of the reasons. It also |
| > simplified a lot of code. |
|
|
| How much simpler can you get than fixed-length records? |
|
|
| Of course, then there are 2 code paths, 1 for fixed length, and |
| 1 for variable length. |
|
|
| |
| + |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "they love our milk and honey, but preach about another | |
| | way of living" | |
| | Merle Haggard, "The Fighting Side Of Me" | |
| + |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 8 10:38:00 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id D658F4760AA |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 10:37:59 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 14D70475BD7 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 10:37:59 -0400 (EDT) |
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| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g98Ec2hR001929; |
| Tue, 8 Oct 2002 10:38:02 -0400 (EDT) |
| To: Ron Johnson <ron.l.johnson@cox.net> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: [GENERAL] Large databases, performance |
| In-reply-to: <1034085052.1094.14.camel@haggis> |
| References: <3DA1E50F.4394.107FF85D@localhost> |
| <3DA2BE03.3674.13CF7DD1@localhost> <20021008072047.GB558@svana.org> |
| <1034085052.1094.14.camel@haggis> |
| Comments: In-reply-to Ron Johnson <ron.l.johnson@cox.net> |
| message dated "08 Oct 2002 08:50:52 -0500" |
| Date: Tue, 08 Oct 2002 10:38:02 -0400 |
| Message-ID: <1928.1034087882@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/60 |
| X-Sequence-Number: 77 |
|
|
| Ron Johnson <ron.l.johnson@cox.net> writes: |
| > Not only that, but you get INSERT, UPDATE, DELETE and SELECT performance |
| > gains with fixed length records, since you don't get fragmentation. |
| |
| That argument loses a lot of its force when you consider that Postgres |
| uses non-overwriting storage management. We never do an UPDATE in-place |
| anyway, and so it matters little whether the updated record is the same |
| size as the original. |
| |
| >> Well, maybe. But since 7.1 or so char() and varchar() simply became text |
| >> with some length restrictions. This was one of the reasons. It also |
| >> simplified a lot of code. |
| |
| > How much simpler can you get than fixed-length records? |
| |
| It's not simpler: it's more complicated, because you need an additional |
| input item to figure out the size of any given column in a record. |
| Making sure that that info is available every place it's needed is one |
| of the costs of supporting a feature like this. |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 8 10:41:20 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id D1577476950 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 10:41:19 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id B1881476992 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 10:41:14 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g98EgrE13773 |
| for <pgsql-performance@postgresql.org>; Tue, 8 Oct 2002 20:12:53 +0530 |
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| for <pgsql-performance@postgresql.org>; Tue, 8 Oct 2002 20:12:53 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-performance@postgresql.org |
| Date: Tue, 08 Oct 2002 20:11:47 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [GENERAL] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA33C03.31407.15BBAE9C@localhost> |
| References: <1034085052.1094.14.camel@haggis> |
| In-reply-to: <1928.1034087882@sss.pgh.pa.us> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
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|
|
| On 8 Oct 2002 at 10:38, Tom Lane wrote: |
|
|
| > Ron Johnson <ron.l.johnson@cox.net> writes: |
| > It's not simpler: it's more complicated, because you need an additional |
| > input item to figure out the size of any given column in a record. |
| > Making sure that that info is available every place it's needed is one |
| > of the costs of supporting a feature like this. |
| |
| I understand. Can we put this in say page header instead of tuple header. While |
| all the arguments you have put are really good, the stellar redundancy |
| certainly can do with a mid-way solution. |
| |
| Just a thought.. |
| |
| Bye |
| Shridhar |
| |
| -- |
| bit, n: A unit of measure applied to color. Twenty-four-bit color refers to |
| expensive $3 color as opposed to the cheaper 25 cent, or two-bit, color that |
| use to be available a few years ago. |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 11:17:06 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 410DA475F84 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:17:05 -0400 (EDT) |
| Received: from lakemtao01.cox.net (lakemtao01.cox.net [68.1.17.244]) |
| by postgresql.org (Postfix) with ESMTP id 95A27475F32 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:17:04 -0400 (EDT) |
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| id <20021008151709.OQAG1310.lakemtao01.cox.net@localhost.localdomain> |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:17:09 -0400 |
| Subject: Re: [GENERAL] Large databases, performance |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <1928.1034087882@sss.pgh.pa.us> |
| References: <3DA1E50F.4394.107FF85D@localhost> |
| <3DA2BE03.3674.13CF7DD1@localhost> <20021008072047.GB558@svana.org> |
| <1034085052.1094.14.camel@haggis> <1928.1034087882@sss.pgh.pa.us> |
| Content-Type: text/plain |
| Content-Transfer-Encoding: 7bit |
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| Date: 08 Oct 2002 10:16:55 -0500 |
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| Mime-Version: 1.0 |
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| X-Archive-Number: 200210/62 |
| X-Sequence-Number: 79 |
| |
| On Tue, 2002-10-08 at 09:38, Tom Lane wrote: |
| > Ron Johnson <ron.l.johnson@cox.net> writes: |
| > > Not only that, but you get INSERT, UPDATE, DELETE and SELECT performance |
| > > gains with fixed length records, since you don't get fragmentation. |
| > |
| > That argument loses a lot of its force when you consider that Postgres |
| > uses non-overwriting storage management. We never do an UPDATE in-place |
| > anyway, and so it matters little whether the updated record is the same |
| > size as the original. |
|
|
| Must you update any relative indexes, in order to point to the |
| new location of the record? |
|
|
| > >> Well, maybe. But since 7.1 or so char() and varchar() simply became text |
| > >> with some length restrictions. This was one of the reasons. It also |
| > >> simplified a lot of code. |
| > |
| > > How much simpler can you get than fixed-length records? |
| > |
| > It's not simpler: it's more complicated, because you need an additional |
| > input item to figure out the size of any given column in a record. |
|
|
| With fixed-length, why? From the metadata, you can compute the intra- |
| record offsets. That's how it works with the commercial RDBMS that |
| I use at work. |
| |
| On that system, even variable-length records don't need record-size |
| fields. Any repeating text (more that ~4 chars) is replaced with |
| run-length encoding. This includes the phantom spaces at the end |
| of the field. |
|
|
| > Making sure that that info is available every place it's needed is one |
| > of the costs of supporting a feature like this. |
| |
| -- |
| +------------------------------------------------------------+ |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "they love our milk and honey, but preach about another | |
| | way of living" | |
| | Merle Haggard, "The Fighting Side Of Me" | |
| +------------------------------------------------------------+ |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 11:35:12 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 58BB9476773 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:35:11 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id B7D584766E6 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:35:10 -0400 (EDT) |
| Received: from [63.195.55.98] (account <josh@agliodbs.com>) |
| by davinci.ethosmedia.com (CommuniGate Pro WebUser 3.5.9) |
| with HTTP id 1775407; Tue, 08 Oct 2002 08:33:53 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: CHAR, VARCHAR, TEXT (Was Large Databases) |
| To: Ron Johnson <ron.l.johnson@cox.net>, |
| pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Tue, 08 Oct 2002 08:33:53 -0700 |
| Message-ID: <web-1775407@davinci.ethosmedia.com> |
| In-Reply-To: <1034090215.1094.42.camel@haggis> |
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| X-Archive-Number: 200210/63 |
| X-Sequence-Number: 80 |
| |
| Ron, Shridhar, |
| |
| Maybe I missed something on this thread, but can either of you give me |
| an example of a real database where the PostgreSQL approach of "all |
| strings are TEXT" versus the more traditional CHAR implementation have |
| resulted in measurable performance loss? |
| |
| Otherwise, this discussion is rather academic ... |
| |
| -Josh Berkus |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 11:51:10 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id CD04C47627C |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:51:08 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 218004761C2 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 11:51:08 -0400 (EDT) |
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| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g98FpChR002503; |
| Tue, 8 Oct 2002 11:51:12 -0400 (EDT) |
| To: Ron Johnson <ron.l.johnson@cox.net> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: [GENERAL] Large databases, performance |
| In-reply-to: <1034090215.1094.42.camel@haggis> |
| References: <3DA1E50F.4394.107FF85D@localhost> |
| <3DA2BE03.3674.13CF7DD1@localhost> <20021008072047.GB558@svana.org> |
| <1034085052.1094.14.camel@haggis> <1928.1034087882@sss.pgh.pa.us> |
| <1034090215.1094.42.camel@haggis> |
| Comments: In-reply-to Ron Johnson <ron.l.johnson@cox.net> |
| message dated "08 Oct 2002 10:16:55 -0500" |
| Date: Tue, 08 Oct 2002 11:51:12 -0400 |
| Message-ID: <2502.1034092272@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/64 |
| X-Sequence-Number: 81 |
| |
| Ron Johnson <ron.l.johnson@cox.net> writes: |
| > On Tue, 2002-10-08 at 09:38, Tom Lane wrote: |
| >> That argument loses a lot of its force when you consider that Postgres |
| >> uses non-overwriting storage management. We never do an UPDATE in-place |
| >> anyway, and so it matters little whether the updated record is the same |
| >> size as the original. |
| |
| > Must you update any relative indexes, in order to point to the |
| > new location of the record? |
| |
| We make new index entries for the new record, yes. Both the old and new |
| records must be indexed (until one or the other is garbage-collected by |
| VACUUM) so that transactions can find whichever version they are |
| supposed to be able to see according to the tuple visibility rules. |
| |
| >> It's not simpler: it's more complicated, because you need an additional |
| >> input item to figure out the size of any given column in a record. |
| |
| > With fixed-length, why? From the metadata, you can compute the intra- |
| > record offsets. |
| |
| Sure, but you need an additional item of metadata than you otherwise |
| would (this is atttypmod, in Postgres terms). I'm not certain that the |
| typmod is available everyplace that would need to be able to figure out |
| the physical width of a column. |
|
|
| > On that system, even variable-length records don't need record-size |
| > fields. Any repeating text (more that ~4 chars) is replaced with |
| > run-length encoding. This includes the phantom spaces at the end |
| > of the field. |
| |
| Interesting that you should bring that up in the context of an argument |
| for supporting fixed-width fields ;-). Doesn't any form of data |
| compression bring you right back into variable-width land? |
|
|
| Postgres' approach to data compression is that it's done per-field, |
| and only on variable-width fields. We steal a couple of bits from the |
| length word to allow flagging of compressed and out-of-line values. |
| If we were to make CHAR(n) fixed-width then it would lose the ability |
| to participate in either compression or out-of-line storage. |
|
|
| Between that and the multibyte-encoding issue, I think it's very |
| difficult to make a case that the general-purpose CHAR(n) type should |
| be implemented as fixed-width. If someone has a specialized application |
| where they need a restricted fixed-width string type, it's not that |
| hard to make a user-defined type that supports only a single column |
| width (and thereby gets around the typmod issue). So I'm satisfied with |
| saying "define your own type if you want this". |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 13:42:36 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 98F67475AFA |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 13:42:35 -0400 (EDT) |
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| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 13:42:35 -0400 |
| Subject: Re: CHAR, VARCHAR, TEXT (Was Large Databases) |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <web-1775407@davinci.ethosmedia.com> |
| References: <web-1775407@davinci.ethosmedia.com> |
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| Date: 08 Oct 2002 12:42:20 -0500 |
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| |
| On Tue, 2002-10-08 at 10:33, Josh Berkus wrote: |
| > Ron, Shridhar, |
| > |
| > Maybe I missed something on this thread, but can either of you give me |
| > an example of a real database where the PostgreSQL approach of "all |
| > strings are TEXT" versus the more traditional CHAR implementation have |
| > resulted in measurable performance loss? |
| |
| ?????? |
| |
| > Otherwise, this discussion is rather academic ... |
| |
| -- |
| +------------------------------------------------------------+ |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "they love our milk and honey, but preach about another | |
| | way of living" | |
| | Merle Haggard, "The Fighting Side Of Me" | |
| +------------------------------------------------------------+ |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 18:45:36 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: Ron Johnson <ron.l.johnson@cox.net>, |
| pgsql-performance@postgresql.org |
| Subject: Re: CHAR, VARCHAR, TEXT (Was Large Databases) |
| Date: Tue, 8 Oct 2002 15:44:36 -0700 |
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| <1034098940.1336.39.camel@haggis> |
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| |
| |
| Ron, |
| |
| > > Maybe I missed something on this thread, but can either of you give me |
| > > an example of a real database where the PostgreSQL approach of "all |
| > > strings are TEXT" versus the more traditional CHAR implementation have |
| > > resulted in measurable performance loss? |
| > |
| > ?????? |
| |
| In other words, if it ain't broke, don't fix it. |
| |
| --=20 |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
| |
| From pgsql-general-owner@postgresql.org Tue Oct 8 19:00:32 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 4ABB1476390; Tue, 8 Oct 2002 19:00:23 -0400 (EDT) |
| Received: from svana.org (t1-1-076.dialup.apex.net.au [203.20.62.76]) |
| by postgresql.org (Postfix) with ESMTP |
| id E5DDC47627C; Tue, 8 Oct 2002 19:00:21 -0400 (EDT) |
| Received: from kleptog by svana.org with local (Exim 3.35 #1 (Debian)) |
| id 17z3C3-0002Gs-00; Wed, 09 Oct 2002 08:51:11 +1000 |
| Date: Wed, 9 Oct 2002 08:51:11 +1000 |
| From: Martijn van Oosterhout <kleptog@svana.org> |
| To: Zeugswetter Andreas SB SD <ZeugswetterA@spardat.at> |
| Cc: Manfred Koizar <mkoi-pg@aon.at>, |
| shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [HACKERS] Large databases, performance |
| Message-ID: <20021008225111.GA8663@svana.org> |
| Reply-To: Martijn van Oosterhout <kleptog@svana.org> |
| Mail-Followup-To: Zeugswetter Andreas SB SD <ZeugswetterA@spardat.at>, |
| Manfred Koizar <mkoi-pg@aon.at>, |
| shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| References: <46C15C39FEB2C44BA555E356FBCD6FA4887A5A@m0114.s-mxs.net> |
| Mime-Version: 1.0 |
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| X-Archive-Number: 200210/473 |
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| |
| On Mon, Oct 07, 2002 at 05:42:12PM +0200, Zeugswetter Andreas SB SD wrote: |
| > > Hackers, do you think it's possible to hack together a quick and dirty |
| > > patch, so that string length is represented by one byte? IOW can a |
| > > database be built that doesn't contain any char/varchar/text value |
| > > longer than 255 characters in the catalog? |
| > |
| > Since he is only using fixchar how about doing a fixchar implemetation, that |
| > does not store length at all ? It is the same for every row anyways ! |
| |
| Remember that in Unicode, 1 char != 1 byte. In fact, any encoding that's not |
| Latin will have a problem. I guess you could put a warning on it: not for |
| use for asian character sets. So what do you do if someone tries to insert |
| such a string anyway? |
|
|
| Perhaps a better approach is to vary the number of bytes used for the |
| length. So one byte for lengths < 64, two bytes for lengths < 16384. |
| Unfortunatly, two bits in the length are already used (IIRC) for other |
| things making it a bit more tricky. |
| |
| Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ |
| > There are 10 kinds of people in the world, those that can do binary |
| > arithmetic and those that can't. |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 19:37:42 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1477F475B33 |
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| Tue, 8 Oct 2002 19:37:40 -0400 (EDT) |
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| Tue, 8 Oct 2002 19:37:39 -0400 (EDT) |
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| charset="iso-8859-1" |
| From: Josh Berkus <josh@agliodbs.com> |
| Organization: Aglio Database Solutions |
| To: Ron Johnson <ron.l.johnson@cox.net>, |
| pgsql-performance@postgresql.org |
| Subject: Re: CHAR, VARCHAR, TEXT (Was Large Databases) |
| Date: Tue, 8 Oct 2002 16:36:40 -0700 |
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| <200210081544.36139.josh@agliodbs.com> |
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| |
| |
| Ron, |
| |
| > > > > Maybe I missed something on this thread, but can either of you give |
| > > > > me an example of a real database where the PostgreSQL approach of |
| > > > > "all strings are TEXT" versus the more traditional CHAR |
| > > > > implementation have resulted in measurable performance loss? |
| > > > |
| > > > ?????? |
| > > |
| > > In other words, if it ain't broke, don't fix it. |
| > |
| > Well, does Really Slow Performance qualify as "broke"? |
| |
| That's what I was asking. Can you explain where your slow performance is= |
| =20 |
| attibutable to the CHAR implementation issues? I missed that, if it was= |
| =20 |
| explained earlier in the thread. |
|
|
| |
| Josh Berkus |
| josh@agliodbs.com |
| Aglio Database Solutions |
| San Francisco |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 8 23:47:28 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 9173B475FC5 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 23:47:26 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id F320A475FB8 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 23:47:25 -0400 (EDT) |
| Received: from [63.195.55.98] (account <josh@agliodbs.com>) |
| by davinci.ethosmedia.com (CommuniGate Pro WebUser 3.5.9) |
| with HTTP id 1776486 for <pgsql-performance@postgresql.org>; |
| Tue, 08 Oct 2002 20:46:12 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: What does this tell me? |
| To: pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Tue, 08 Oct 2002 20:46:12 -0700 |
| Message-ID: <web-1776486@davinci.ethosmedia.com> |
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|
|
| Folks, |
|
|
| I'm still having trouble with my massive data transformation procedures |
| taking forever to finish. Particularly, many of them will get about |
| 1/2 way through, and then I will start seeing this in the log: |
| |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E4 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E5 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E6 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E7 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E8 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000E9 |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000EA |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000EB |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000EC |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000ED |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000EE |
| 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| 0000000A000000EF |
| 2002-10-08 20:37:13 DEBUG: reaping dead processes |
| 2002-10-08 20:37:13 DEBUG: child process (pid 15270) exited with exit |
| code 0 |
| |
| ... repeat ad nauseum. The problem is, each "recycle transaction log |
| ... reaping dead child process" cycle takes about 4-7 minutes ... |
| meaning that the procedure can take up to 1/2 hour to finish, and |
| sometimes not finish at all. |
| |
| Obviously, the system is telling me that it is running out of resources |
| somehow. But I'm at my wit's end to figure out what resources, |
| exactly. Suggestions? |
| |
| -Josh Berkus |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 23:49:46 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 4EE2D475E40 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 23:49:45 -0400 (EDT) |
| Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) |
| by postgresql.org (Postfix) with ESMTP id 60949475DAD |
| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 23:49:43 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g993nab27932; |
| Tue, 8 Oct 2002 23:49:36 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210090349.g993nab27932@candle.pha.pa.us> |
| Subject: Re: What does this tell me? |
| In-Reply-To: <web-1776486@davinci.ethosmedia.com> |
| To: Josh Berkus <josh@agliodbs.com> |
| Date: Tue, 8 Oct 2002 23:49:36 -0400 (EDT) |
| Cc: pgsql-performance@postgresql.org |
| X-Mailer: ELM [version 2.4ME+ PL99 (25)] |
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| |
| |
| I think all it means is that is doesn't need some of the pg_clog files |
| and is reusing them, basically meaning you are pushing through lots of |
| transactions. I don't see it as a problem. |
| |
| --------------------------------------------------------------------------- |
| |
| Josh Berkus wrote: |
| > Folks, |
| > |
| > I'm still having trouble with my massive data transformation procedures |
| > taking forever to finish. Particularly, many of them will get about |
| > 1/2 way through, and then I will start seeing this in the log: |
| > |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E4 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E5 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E6 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E7 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E8 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E9 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EA |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EB |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EC |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000ED |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EE |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EF |
| > 2002-10-08 20:37:13 DEBUG: reaping dead processes |
| > 2002-10-08 20:37:13 DEBUG: child process (pid 15270) exited with exit |
| > code 0 |
| > |
| > ... repeat ad nauseum. The problem is, each "recycle transaction log |
| > ... reaping dead child process" cycle takes about 4-7 minutes ... |
| > meaning that the procedure can take up to 1/2 hour to finish, and |
| > sometimes not finish at all. |
| > |
| > Obviously, the system is telling me that it is running out of resources |
| > somehow. But I'm at my wit's end to figure out what resources, |
| > exactly. Suggestions? |
| > |
| > -Josh Berkus |
| > |
| > |
| > TIP 4: Don't 'kill -9' the postmaster |
| > |
| |
| -- |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 8 23:50:50 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Date: Tue, 8 Oct 2002 20:50:43 -0700 |
| From: Sean Chittenden <sean@chittenden.org> |
| To: Josh Berkus <josh@agliodbs.com> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: What does this tell me? |
| Message-ID: <20021009035043.GC34365@perrin.int.nxad.com> |
| References: <web-1776486@davinci.ethosmedia.com> |
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| |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E4 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E5 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E6 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E7 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E8 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000E9 |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EA |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EB |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EC |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000ED |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EE |
| > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > 0000000A000000EF |
| > 2002-10-08 20:37:13 DEBUG: reaping dead processes |
| > 2002-10-08 20:37:13 DEBUG: child process (pid 15270) exited with exit |
| > code 0 |
| > |
| > ... repeat ad nauseum. The problem is, each "recycle transaction |
| > log ... reaping dead child process" cycle takes about 4-7 minutes |
| > ... meaning that the procedure can take up to 1/2 hour to finish, |
| > and sometimes not finish at all. |
| > |
| > Obviously, the system is telling me that it is running out of |
| > resources somehow. But I'm at my wit's end to figure out what |
| > resources, exactly. Suggestions? |
| |
| You're running out of WAL log space, iirc. Increase the number of WAL |
| logs available and you should be okay. If you're experiencing this |
| halfway through, I'd increase the size by 50%, say maybe 60-70% for |
| good measure. -sc |
|
|
| |
| Sean Chittenden |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 8 23:55:37 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 250B64761BF |
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| Tue, 8 Oct 2002 23:55:37 -0400 (EDT) |
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| for <pgsql-performance@postgresql.org>; |
| Tue, 8 Oct 2002 23:55:35 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g993tAU02565; |
| Tue, 8 Oct 2002 23:55:10 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210090355.g993tAU02565@candle.pha.pa.us> |
| Subject: Re: What does this tell me? |
| In-Reply-To: <20021009035043.GC34365@perrin.int.nxad.com> |
| To: Sean Chittenden <sean@chittenden.org> |
| Date: Tue, 8 Oct 2002 23:55:10 -0400 (EDT) |
| Cc: Josh Berkus <josh@agliodbs.com>, pgsql-performance@postgresql.org |
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| X-Archive-Number: 200210/72 |
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|
|
| Sean Chittenden wrote: |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E4 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E5 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E6 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E7 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E8 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000E9 |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000EA |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000EB |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000EC |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000ED |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000EE |
| > > 2002-10-08 20:37:13 DEBUG: recycled transaction log file |
| > > 0000000A000000EF |
| > > 2002-10-08 20:37:13 DEBUG: reaping dead processes |
| > > 2002-10-08 20:37:13 DEBUG: child process (pid 15270) exited with exit |
| > > code 0 |
| > > |
| > > ... repeat ad nauseum. The problem is, each "recycle transaction |
| > > log ... reaping dead child process" cycle takes about 4-7 minutes |
| > > ... meaning that the procedure can take up to 1/2 hour to finish, |
| > > and sometimes not finish at all. |
| > > |
| > > Obviously, the system is telling me that it is running out of |
| > > resources somehow. But I'm at my wit's end to figure out what |
| > > resources, exactly. Suggestions? |
| > |
| > You're running out of WAL log space, iirc. Increase the number of WAL |
| > logs available and you should be okay. If you're experiencing this |
| > halfway through, I'd increase the size by 50%, say maybe 60-70% for |
| > good measure. -sc |
| |
| Oh, yes, you are right. My hardware tuning guide mentions it. Strange |
| it is called the transaction log file: |
| |
| http://www.ca.postgresql.org/docs/momjian/hw_performance/ |
| |
| Unless you are seeing this more freqently than every minute, it should |
| be fine. |
| |
| -- |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:03:15 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| with HTTP id 1776515; Tue, 08 Oct 2002 21:01:58 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: What does this tell me? |
| To: Bruce Momjian <pgman@candle.pha.pa.us>, |
| Sean Chittenden <sean@chittenden.org> |
| Cc: Josh Berkus <josh@agliodbs.com>, pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Tue, 08 Oct 2002 21:01:58 -0700 |
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| |
| Bruce, Sean, |
| |
| > Oh, yes, you are right. My hardware tuning guide mentions it. |
| > Strange |
| > it is called the transaction log file: |
| > |
| > http://www.ca.postgresql.org/docs/momjian/hw_performance/ |
| > |
| > Unless you are seeing this more freqently than every minute, it |
| > should |
| > be fine. |
| |
| Actually, it's apparently a real problem, because the function never |
| completes. Each cycle of "recycling transaction logs" takes longer |
| and longer, and eventually locks up completely. |
|
|
| What the function is doing is a succession of data cleanup procedures, |
| updating the same table about 50 times. I will be very thankful for |
| the day when I can commit within a procedure. |
|
|
| Unfortunately, I am already at the maximum number of WAL files (64). |
| What do I do now? |
|
|
| -Josh Berkus |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:07:33 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1705D475FC5 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 9 Oct 2002 00:07:32 -0400 (EDT) |
| Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) |
| by postgresql.org (Postfix) with ESMTP id 07AD9475AD7 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 9 Oct 2002 00:07:30 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g9947O904553; |
| Wed, 9 Oct 2002 00:07:24 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210090407.g9947O904553@candle.pha.pa.us> |
| Subject: Re: What does this tell me? |
| In-Reply-To: <web-1776515@davinci.ethosmedia.com> |
| To: Josh Berkus <josh@agliodbs.com> |
| Date: Wed, 9 Oct 2002 00:07:24 -0400 (EDT) |
| Cc: Sean Chittenden <sean@chittenden.org>, |
| pgsql-performance@postgresql.org |
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|
|
| Josh Berkus wrote: |
| > Bruce, Sean, |
| > |
| > > Oh, yes, you are right. My hardware tuning guide mentions it. |
| > > Strange |
| > > it is called the transaction log file: |
| > > |
| > > http://www.ca.postgresql.org/docs/momjian/hw_performance/ |
| > > |
| > > Unless you are seeing this more freqently than every minute, it |
| > > should |
| > > be fine. |
| > |
| > Actually, it's apparently a real problem, because the function never |
| > completes. Each cycle of "recycling transaction logs" takes longer |
| > and longer, and eventually locks up completely. |
| > |
| > What the function is doing is a succession of data cleanup procedures, |
| > updating the same table about 50 times. I will be very thankful for |
| > the day when I can commit within a procedure. |
| > |
| > Unfortunately, I am already at the maximum number of WAL files (64). |
| > What do I do now? |
| |
| Wow, that is interesting. I thought one big transaction wouldn't lock |
| up the WAL records. I figured there would be a CHECKPOINT, and then the |
| WAL records could be recycled, even though the transaction is still |
| open. |
|
|
| Where do you see 64 as the maximum number of WAL segments. What is your |
| checkpoint_segments value? The actual number of files shouldn't be much |
| more than twice that value. What PostgreSQL version are you using? |
| |
| -- |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:17:48 2002 |
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| Date: Tue, 8 Oct 2002 21:17:50 -0700 |
| From: Sean Chittenden <sean@chittenden.org> |
| To: Josh Berkus <josh@agliodbs.com> |
| Cc: Bruce Momjian <pgman@candle.pha.pa.us>, |
| pgsql-performance@postgresql.org |
| Subject: Re: What does this tell me? |
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| |
| > > Oh, yes, you are right. My hardware tuning guide mentions it. |
| > > Strange it is called the transaction log file: |
| > > |
| > > http://www.ca.postgresql.org/docs/momjian/hw_performance/ |
| > > |
| > > Unless you are seeing this more freqently than every minute, it |
| > > should |
| > > be fine. |
| > |
| > Actually, it's apparently a real problem, because the function never |
| > completes. Each cycle of "recycling transaction logs" takes longer |
| > and longer, and eventually locks up completely. |
| > |
| > What the function is doing is a succession of data cleanup |
| > procedures, updating the same table about 50 times. I will be very |
| > thankful for the day when I can commit within a procedure. |
| > |
| > Unfortunately, I am already at the maximum number of WAL files (64). |
| > What do I do now? |
|
|
| Isn't it possible to increase the size of your wal logs? I seem to |
| remember a tunable existing, but I can't find it in the default |
| config. Someone else know how off the top of their head? -sc |
|
|
| |
| Sean Chittenden |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:35:08 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| with HTTP id 1776567; Tue, 08 Oct 2002 21:33:52 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: What does this tell me? |
| To: Bruce Momjian <pgman@candle.pha.pa.us>, |
| Josh Berkus <josh@agliodbs.com> |
| Cc: pgsql-performance@postgresql.org |
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|
|
| Bruce, |
|
|
| > > First, an interesting wierdness from the VACUUM FULL ANALYZE: |
| > > Analyzing elbs_clidesc |
| > > 2002-10-08 21:08:08 DEBUG: SIInsertDataEntry: table is 70% full, |
| > > signaling postmaster |
| > > |
| > > Huh? |
| > |
| > Well, you are dealing with elbs. That is the problem. ;-) |
|
|
| <grin> As you probably guessed, the purpose of these procedures is to |
| take a large amount (about 60mb) of not-normalized data from ELBS and |
| normalize it for our web-based case management system. |
|
|
| What's really frustrating about it is that we're only going to be doing |
| this for 2-3 months before we jettison ELBS for reasons that should be |
| obvious to you. But for those 2-3 months, the data transfer needs to |
| work well, and right now it doesn't even finish. |
| |
| > You shoulnd't need that and it shouldn't lock up when it gets to 64. |
| > It |
| > should checkpoint and move on. The only problem with it being lower |
| > is |
| > that it will checkpoint more often. |
| |
| Well, I'll try 128 and see if that helps any. |
|
|
| > |
| > > Rest of postgresql.conf params after my signature. All |
| > suggestions |
| > > are welcome. This server has been acting "sick" since I started |
| > with |
| > > it, under-performing my workstation and MS SQL Server. Either I've |
| > set |
| > > something wrong, or there's a hardware problem I need to track |
| > down. |
| > > |
| > > BTW, is there any problem for postgres in turning the fill access |
| > time |
| > > recorder in the host filesystem off? This is often good for a |
| > minor |
| > > performance gain. |
| > |
| > No problem. |
| > |
| > You might want to try pgbench and see if that works. |
|
|
| Yeah. I was planning on that -- as well as the postgresql.conf tuner |
| |
| little working time. |
|
|
| -Josh Berkus |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:38:15 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1AAFD475FBA |
| for <pgsql-performance@postgresql.org>; |
| Wed, 9 Oct 2002 00:38:14 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 6185D475EA4 |
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| Wed, 9 Oct 2002 00:38:12 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g994cAU07439; |
| Wed, 9 Oct 2002 00:38:10 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210090438.g994cAU07439@candle.pha.pa.us> |
| Subject: Re: What does this tell me? |
| In-Reply-To: <web-1776567@davinci.ethosmedia.com> |
| To: Josh Berkus <josh@agliodbs.com> |
| Date: Wed, 9 Oct 2002 00:38:10 -0400 (EDT) |
| Cc: pgsql-performance@postgresql.org |
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|
|
| Josh Berkus wrote: |
| > > > Rest of postgresql.conf params after my signature. All |
| > > suggestions |
| > > > are welcome. This server has been acting "sick" since I started |
| > > with |
| > > > it, under-performing my workstation and MS SQL Server. Either I've |
| > > set |
| > > > something wrong, or there's a hardware problem I need to track |
| > > down. |
| > > > |
| > > > BTW, is there any problem for postgres in turning the fill access |
| > > time |
| > > > recorder in the host filesystem off? This is often good for a |
| > > minor |
| > > > performance gain. |
| > > |
| > > No problem. |
| > > |
| > > You might want to try pgbench and see if that works. |
| > |
| > Yeah. I was planning on that -- as well as the postgresql.conf tuner |
| > |
| > little working time. |
|
|
| I was suggesting pgbench because the system should never lock up on you. |
| Maybe something is very wrong. |
|
|
| What happens if you issue the CHECKPOINT command? |
|
|
| |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 00:56:43 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Wed, 9 Oct 2002 00:56:42 -0400 (EDT) |
| Received: from joeconway.com (unknown [63.210.180.150]) |
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| Date: Tue, 08 Oct 2002 21:55:21 -0700 |
| From: Joe Conway <mail@joeconway.com> |
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| To: Josh Berkus <josh@agliodbs.com> |
| Cc: Bruce Momjian <pgman@candle.pha.pa.us>, |
| Sean Chittenden <sean@chittenden.org>, pgsql-performance@postgresql.org |
| Subject: Re: What does this tell me? |
| References: <web-1776515@davinci.ethosmedia.com> |
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|
|
| Josh Berkus wrote: |
| > What the function is doing is a succession of data cleanup procedures, |
| > updating the same table about 50 times. I will be very thankful for |
| > the day when I can commit within a procedure. |
|
|
| If that's the case, can you split the work up into multiple functions, and |
| execute them all from a shell script? Or perhaps even offload some of the data |
| massaging to perl or something? (It would be easier to recommend alternate |
| approaches with more details.) |
| |
| Joe |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 9 01:22:36 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 09F9E47651C |
| for <pgsql-performance@postgresql.org>; |
| Wed, 9 Oct 2002 01:22:35 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 6A65D4764C8 |
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| Wed, 9 Oct 2002 01:22:34 -0400 (EDT) |
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| Wed, 9 Oct 2002 01:22:26 -0400 (EDT) |
| To: "Josh Berkus" <josh@agliodbs.com> |
| Cc: Bruce Momjian <pgman@candle.pha.pa.us>, |
| Sean Chittenden <sean@chittenden.org>, pgsql-performance@postgresql.org |
| Subject: Re: What does this tell me? |
| In-reply-to: <web-1776515@davinci.ethosmedia.com> |
| References: <web-1776515@davinci.ethosmedia.com> |
| Comments: In-reply-to "Josh Berkus" <josh@agliodbs.com> |
| message dated "Tue, 08 Oct 2002 21:01:58 -0700" |
| Date: Wed, 09 Oct 2002 01:22:26 -0400 |
| Message-ID: <17558.1034140946@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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| |
| "Josh Berkus" <josh@agliodbs.com> writes: |
| > Actually, it's apparently a real problem, because the function never |
| > completes. Each cycle of "recycling transaction logs" takes longer |
| > and longer, and eventually locks up completely. |
| > What the function is doing is a succession of data cleanup procedures, |
| > updating the same table about 50 times. I will be very thankful for |
| > the day when I can commit within a procedure. |
|
|
| I think you are barking up the wrong tree. |
|
|
| The messages you show are perfectly normal operation, and prove nothing |
| much except that you pumped a lot of database updates through the |
| system. I think there's something wrong with your data transformation |
| application logic; or perhaps you are pumping so many updates through |
| your tables that you need some intermediate VACUUMs to get rid of |
| dead tuples. But messing with the WAL log parameters isn't going to |
| do a darn thing for you ... IMHO anyway. |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 01:23:57 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id A55FE475E60 |
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| Wed, 9 Oct 2002 01:23:56 -0400 (EDT) |
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| Wed, 9 Oct 2002 01:23:56 -0400 (EDT) |
| Received: from [63.195.55.98] (account <josh@agliodbs.com>) |
| by davinci.ethosmedia.com (CommuniGate Pro WebUser 3.5.9) |
| with HTTP id 1776618; Tue, 08 Oct 2002 22:22:37 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: What does this tell me? |
| To: Joe Conway <mail@joeconway.com>, Josh Berkus <josh@agliodbs.com> |
| Cc: Bruce Momjian <pgman@candle.pha.pa.us>, |
| Sean Chittenden <sean@chittenden.org>, pgsql-performance@postgresql.org |
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| Date: Tue, 08 Oct 2002 22:22:37 -0700 |
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|
|
| Joe, |
|
|
| > If that's the case, can you split the work up into multiple |
| > functions, and execute them all from a shell script? Or perhaps even |
| > offload some of the data massaging to perl or something? (It would be |
| > easier to recommend alternate approaches with more details.) |
| |
| I've already split it up into 11 functions, which are being managed |
| through Perl with ANALYZE statements between. Breaking it down |
| further would be really unmanageable. |
|
|
| Not to be mean or anything (after all, I just joined pgsql-advocacy), |
| I'm getting *much* worse performance on large data transformations from |
| PostgreSQL 7.2.1, than I get from SQL Server 7.0 on inferior hardware |
| (at least, except where SQL Server 7.0 crashes). I really am determined |
| to prove that it's because I've misconfigured it, and I thank all of |
| you for your help in doing so. |
| |
| PGBench Results: |
| transaction type: TPC-B (sort of) |
| scaling factor: 10 |
| number of clients: 100 |
| number of transactions per client: 10 |
| number of transactions actually processed: 1000/1000 |
| tps = 93.206356(including connections establishing) |
| tps = 103.237007(excluding connections establishing) |
| |
| Of course, I don't have much to compare these to, so I don't know if |
| that's good or bad. |
|
|
| -Josh Berkus |
|
|
| |
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 03:57:38 2002 |
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| for <shridhar?daithankar@persistent.co.in>; 9 Oct 2002 07:57:27 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Large databases, performance |
| Date: Wed, 09 Oct 2002 10:00:03 +0200 |
| Message-ID: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
| References: <3D9C3E05.7070906@clearmetrix.com> |
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| |
| Content-Type: text/plain; charset=us-ascii |
| Content-Transfer-Encoding: 7bit |
|
|
| On Mon, 07 Oct 2002 15:07:29 +0530, "Shridhar Daithankar" |
| <shridhar_daithankar@persistent.co.in> wrote: |
| >Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. |
|
|
| Shridhar, |
|
|
| here is an implementation of a set of user types: char3, char4, |
| char10. Put the attached files into a new directory contrib/fixchar, |
| make, make install, and run fixchar.sql through psql. Then create |
| your table as |
| CREATE TABLE tbl ( |
| type int, |
| esn char10, |
| min char10, |
| datetime timestamp, |
| opc0 char3, |
| ... |
| rest char4, |
| field0 int, |
| field1 char4, |
| ... |
| ) |
|
|
| This should save 76 bytes per heap tuple and 12 bytes per index tuple, |
| giving a database size of ~ 76 GB. I'd be very interested how this |
| affects performance. |
| |
| Code has been tested for v7.2, it crashes on v7.3 beta 1. If this is |
| a problem, let me know. |
| |
| Servus |
| Manfred |
| |
| ----=_3go7qusj2mfc5mqkb950rta73h7v8jn4qv.MFSBCHJLHS |
| Content-Type: text/plain; charset=us-ascii; name=fixcharNN.sql.in |
| Content-Transfer-Encoding: 7bit |
| Content-Disposition: attachment; filename=fixcharNN.sql.in |
| |
| -- User type charNN: space saving replacement for char(NN) |
| |
| CREATE FUNCTION charNN_in(opaque) |
| RETURNS charNN |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_out(opaque) |
| RETURNS opaque |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE TYPE charNN ( |
| INPUT = charNN_in, |
| OUTPUT = charNN_out, |
| INTERNALLENGTH = NN, |
| ALIGNMENT = char |
| ); |
| |
| -- Operators |
| CREATE FUNCTION charNN_lt(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_le(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_eq(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_ge(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_gt(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE FUNCTION charNN_ne(charNN, charNN) |
| RETURNS boolean |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| CREATE OPERATOR < ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_lt, |
| COMMUTATOR = >, |
| NEGATOR = >=, |
| RESTRICT = scalarltsel, JOIN = scalarltjoinsel |
| ); |
| |
| CREATE OPERATOR <= ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_le, |
| COMMUTATOR = >=, |
| NEGATOR = >, |
| RESTRICT = scalarltsel, JOIN = scalarltjoinsel |
| ); |
| |
| CREATE OPERATOR = ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_eq, |
| COMMUTATOR = =, |
| NEGATOR = !=, |
| RESTRICT = eqsel, JOIN = eqjoinsel |
| ); |
| |
| CREATE OPERATOR >= ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_ge, |
| COMMUTATOR = <=, |
| NEGATOR = <, |
| RESTRICT = scalargtsel, JOIN = scalargtjoinsel |
| ); |
| |
| CREATE OPERATOR > ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_gt, |
| COMMUTATOR = <, |
| NEGATOR = <=, |
| RESTRICT = scalargtsel, JOIN = scalargtjoinsel |
| ); |
| |
| CREATE OPERATOR != ( LEFTARG = charNN, RIGHTARG = charNN, |
| PROCEDURE = charNN_ne, |
| COMMUTATOR = !=, |
| NEGATOR = =, |
| RESTRICT = neqsel, JOIN = neqjoinsel |
| ); |
| |
| -- btree opclass |
| INSERT INTO pg_opclass (opcamid, opcname, opcintype, opcdefault, opckeytype) |
| SELECT a.oid, 'charNN_ops', t.oid, true, 0 |
| FROM pg_am a, pg_type t |
| WHERE a.amname = 'btree' |
| AND t.typname = 'charNN'; |
| |
| --btree strategies |
| CREATE TEMP TABLE charNN_strat ( |
| strat smallint, |
| opr name |
| ); |
| |
| INSERT INTO charNN_strat VALUES (1, '<'); |
| INSERT INTO charNN_strat VALUES (2, '<='); |
| INSERT INTO charNN_strat VALUES (3, '='); |
| INSERT INTO charNN_strat VALUES (4, '>='); |
| INSERT INTO charNN_strat VALUES (5, '>'); |
| |
| SELECT o.oid AS opoid, s.strat |
| INTO TEMP TABLE charNN_ops_tmp |
| FROM pg_operator o, pg_type t, charNN_strat s |
| WHERE t.typname = 'charNN' |
| AND o.oprleft = t.oid |
| AND o.oprright = t.oid |
| AND o.oprname = s.opr; |
| |
| INSERT INTO pg_amop (amopclaid, amopstrategy, amopreqcheck, amopopr) |
| SELECT oc.oid, c.strat, false, c.opoid |
| FROM pg_opclass oc, charNN_ops_tmp c, pg_am a |
| WHERE opcamid = a.oid |
| AND opcname = 'charNN_ops' |
| AND a.amname = 'btree'; |
| |
| |
| -- support routine |
| CREATE FUNCTION charNN_cmp(charNN, charNN) |
| RETURNS integer |
| AS '$libdir/fixchar' |
| LANGUAGE 'c'; |
| |
| INSERT INTO pg_amproc (amopclaid, amprocnum, amproc) |
| SELECT oc.oid, 1, p.oid |
| FROM pg_opclass oc, pg_proc p, pg_am a |
| WHERE a.amname = 'btree' |
| AND oc.opcamid = a.oid |
| AND oc.opcname = 'charNN_ops' |
| AND p.proname = 'charNN_cmp'; |
| |
| |
| ----=_3go7qusj2mfc5mqkb950rta73h7v8jn4qv.MFSBCHJLHS |
| Content-Type: text/plain; charset=us-ascii; name=Makefile |
| Content-Transfer-Encoding: 7bit |
| Content-Disposition: attachment; filename=Makefile |
| |
| # fixchar Makefile |
| # |
| # Experimental code! Use at your own risk! |
| # 2002-10-08 mk |
| |
| subdir = contrib/fixchar |
| top_builddir = ../.. |
| include $(top_builddir)/src/Makefile.global |
| |
| MODULE_big = fixchar |
| OBJS = char3.o char4.o char10.o |
| DATA_built = fixchar.sql |
| DOCS = README.fixchar |
| |
| char%.c: fixcharNN.c.in |
| sed -e 's/NN/$*/g' $< >$@ |
| |
| fixchar.sql: char3.sql char4.sql char10.sql |
| cat $^ >$@ |
| |
| char%.sql: fixcharNN.sql.in |
| sed -e 's/NN/$*/g' $< >$@ |
| |
| include $(top_srcdir)/contrib/contrib-global.mk |
| |
| |
| ----=_3go7qusj2mfc5mqkb950rta73h7v8jn4qv.MFSBCHJLHS |
| Content-Type: text/plain; charset=us-ascii; name=fixcharNN.c.in |
| Content-Transfer-Encoding: 7bit |
| Content-Disposition: attachment; filename=fixcharNN.c.in |
| |
| #include "postgres.h" |
| |
| char *charNN_in(char *cstr); |
| char *charNN_out(char *sstr); |
| bool charNN_lt(char *a, char *b); |
| bool charNN_le(char *a, char *b); |
| bool charNN_eq(char *a, char *b); |
| bool charNN_ge(char *a, char *b); |
| bool charNN_gt(char *a, char *b); |
| bool charNN_ne(char *a, char *b); |
| int4 charNN_cmp(char *a, char *b); |
| |
| char * |
| charNN_in(char *cstr) |
| { |
| char *result; |
| int len; |
| int i; |
| |
| len = strlen(cstr); |
| if (len > NN) |
| len = NN; |
| |
| result = (char *) palloc(NN); |
| for (i = 0; i < len; ++i) |
| result[i] = cstr[i]; |
| |
| for (; i < NN; ++i) |
| result[i] = ' '; |
| |
| return result; |
| }/*charNN_in*/ |
| |
| char * |
| charNN_out(char *sstr) |
| { |
| char *result; |
| int i; |
| |
| if (sstr == NULL) |
| return NULL; |
| |
| result = (char *) palloc(NN + 1); |
| for (i = 0; i < NN; ++i) |
| result[i] = sstr[i]; |
| |
| result[NN] = '\0'; |
| |
| return result; |
| }/*charNN_out*/ |
| |
| bool |
| charNN_lt(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) < 0); |
| }/*charNN_lt*/ |
| |
| bool |
| charNN_le(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) <= 0); |
| }/*charNN_le*/ |
| |
| bool |
| charNN_eq(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) == 0); |
| }/*charNN_eq*/ |
| |
| bool |
| charNN_ge(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) >= 0); |
| }/*charNN_ge*/ |
| |
| bool |
| charNN_gt(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) > 0); |
| }/*charNN_gt*/ |
| |
| bool |
| charNN_ne(char *a, char *b) |
| { |
| return (strncmp(a, b, NN) != 0); |
| }/*charNN_ne*/ |
| |
| int4 |
| charNN_cmp(char *a, char *b) |
| { |
| return strncmp(a, b, NN); |
| }/*charNN_cmp*/ |
| |
| ----=_3go7qusj2mfc5mqkb950rta73h7v8jn4qv.MFSBCHJLHS |
| Content-Type: text/plain; charset=us-ascii; name=README.fixchar |
| Content-Transfer-Encoding: 7bit |
| Content-Disposition: attachment; filename=README.fixchar |
| |
| fixchar |
| ======= |
| |
| User data types char3, char4 and char10 as space saving replacements |
| for char(3), char(4), and char(10) respectively. |
| |
| This is an experimental implementation for Shridhar's high volume |
| performance tests. It is not expected to be usable in any real world |
| application. Known problems are at least: |
|
|
| . There are no casting functions |
| . This does not work with multibyte character sets |
|
|
| Use at your own risk! |
|
|
|
|
| I N S T A L L |
| ============= |
|
|
| . Put these files into contrib/fixchar |
| . cd to contrib/fixchar |
| . make |
| . make install |
| . cd to the directory where PG is installed |
| . bin/psql yourdb |
| yourdb= |
|
|
|
|
| T E S T |
| ======= |
|
|
| CREATE TABLE short ( |
| i INT, |
| c3 char3, |
| c4 char4, |
| c10 char10, |
| primary key (i, c3) |
| ); |
| CREATE TABLE long ( |
| i INT, |
| c3 char(3), |
| c4 char(4), |
| c10 char(10), |
| primary key (i, c3) |
| ); |
| INSERT INTO short VALUES (1, 'aaa', 'aaaa', 'a'); |
| INSERT INTO long VALUES (1, 'aaa', 'aaaa', 'a'); |
| INSERT INTO short SELECT i+1, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+1, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+2, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+2, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+4, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+4, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+8, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+8, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+16, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+16, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+32, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+32, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+64, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+64, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+128, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+128, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+256, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+256, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+512, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+512, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+1024, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+1024, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+2048, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+2048, c3, c4, c10 FROM long; |
| INSERT INTO short SELECT i+4096, c3, c4, c10 FROM short; |
| INSERT INTO long SELECT i+4096, c3, c4, c10 FROM long; |
| VACUUM VERBOSE ANALYZE short; |
| VACUUM VERBOSE ANALYZE long; |
| SELECT relname,reltuples,relpages FROM pg_class WHERE relname NOT LIKE 'pg%'; |
| relname | reltuples | relpages |
| |
| short_pkey | 8192 | 33 |
| short | 8192 | 57 |
| long_pkey | 8192 | 39 |
| long | 8192 | 69 |
| (4 rows) |
|
|
| (2002-10-08 mk) |
|
|
| |
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 04:06:49 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 47B4F475F09 |
| for <pgsql-general@postgresql.org>; |
| Wed, 9 Oct 2002 04:06:47 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id 92045475B84 |
| for <pgsql-general@postgresql.org>; |
| Wed, 9 Oct 2002 04:06:45 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g9988KV04620 |
| for <pgsql-general@postgresql.org>; Wed, 9 Oct 2002 13:38:20 +0530 |
| Received: from daithan (daithan.intranet.pspl.co.in [192.168.7.161]) |
| by www.pspl.co.in (8.11.6/8.11.0) with ESMTP id g9988Jv04605; |
| Wed, 9 Oct 2002 13:38:20 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: Manfred Koizar <mkoi-pg@aon.at>, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Wed, 09 Oct 2002 13:37:13 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA43109.23106.1978CDFD@localhost> |
| In-reply-to: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
| References: <3DA1A331.21316.F7E742B@localhost> |
| X-mailer: Pegasus Mail for Windows (v4.02) |
| Content-type: text/plain; charset=US-ASCII |
| Content-transfer-encoding: 7BIT |
| Content-description: Mail message body |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/488 |
| X-Sequence-Number: 31486 |
|
|
| On 9 Oct 2002 at 10:00, Manfred Koizar wrote: |
|
|
| > On Mon, 07 Oct 2002 15:07:29 +0530, "Shridhar Daithankar" |
| > <shridhar_daithankar@persistent.co.in> wrote: |
| > >Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. |
| > |
| > Shridhar, |
| > |
| > here is an implementation of a set of user types: char3, char4, |
| > char10. Put the attached files into a new directory contrib/fixchar, |
| > make, make install, and run fixchar.sql through psql. Then create |
| > your table as |
| > CREATE TABLE tbl ( |
| > type int, |
| > esn char10, |
| > min char10, |
| > datetime timestamp, |
| > opc0 char3, |
| > ... |
| > rest char4, |
| > field0 int, |
| > field1 char4, |
| > ... |
| > ) |
| > |
| > This should save 76 bytes per heap tuple and 12 bytes per index tuple, |
| > giving a database size of ~ 76 GB. I'd be very interested how this |
| > affects performance. |
| > |
| > Code has been tested for v7.2, it crashes on v7.3 beta 1. If this is |
| > a problem, let me know. |
| |
| Thank you very much for this. I would certainly give it a try. Please be |
| patient as next test is scheuled on monday. |
| |
| Bye |
| Shridhar |
| |
| -- |
| love, n.: When it's growing, you don't mind watering it with a few tears. |
| |
| |
| From pgsql-general-owner@postgresql.org Wed Oct 9 04:25:01 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id E3F4F475EA4 |
| for <pgsql-general@postgresql.org>; |
| Wed, 9 Oct 2002 04:24:59 -0400 (EDT) |
| Received: from www.pspl.co.in (www.pspl.co.in [202.54.11.65]) |
| by postgresql.org (Postfix) with ESMTP id 01978475E60 |
| for <pgsql-general@postgresql.org>; |
| Wed, 9 Oct 2002 04:24:58 -0400 (EDT) |
| Received: (from root@localhost) |
| by www.pspl.co.in (8.11.6/8.11.6) id g998QYO06583 |
| for <pgsql-general@postgresql.org>; Wed, 9 Oct 2002 13:56:34 +0530 |
| Received: from daithan (daithan.intranet.pspl.co.in [192.168.7.161]) |
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| Wed, 9 Oct 2002 13:56:34 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: Manfred Koizar <mkoi-pg@aon.at>, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Wed, 09 Oct 2002 13:55:28 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
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| In-reply-to: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
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| |
| On 9 Oct 2002 at 10:00, Manfred Koizar wrote: |
| |
| > On Mon, 07 Oct 2002 15:07:29 +0530, "Shridhar Daithankar" |
| > <shridhar_daithankar@persistent.co.in> wrote: |
| > >Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. |
| > |
| > Shridhar, |
| > |
| > here is an implementation of a set of user types: char3, char4, |
| > char10. Put the attached files into a new directory contrib/fixchar, |
| > make, make install, and run fixchar.sql through psql. Then create |
| > your table as |
| |
| I had a quick look in things. I think it's a great learning material for pg |
| internals..;-) |
|
|
| I have a suggestion. In README, it should be worth mentioning that, new types |
| can be added just by changin Makefile. e.g. Changing line |
|
|
| OBJS = char3.o char4.o char10.o |
|
|
| to |
|
|
| OBJS = char3.o char4.o char5.o char10.o |
|
|
| would add the datatype char5 as well. |
|
|
| Obviously this is for those who might not take efforts to read the source. ( |
| Personally I wouldn't have, had it been part of entire postgres source dump. |
| Just would have done ./configure;make;make install) |
| |
| Thanks for the solution. It wouldn't have occurred to me in ages to create a |
| type for this. I guess that's partly because never used postgresql beyond |
| select/insert/update/delete. Anyway should have been awake.. |
| |
| Thanks once again |
| |
| |
| Bye |
| Shridhar |
| |
| -- |
| But it's real. And if it's real it can be affected ... we may not be ableto |
| break it, but, I'll bet you credits to Navy Beans we can put a dent in it. |
| deSalle, "Catspaw", stardate 3018.2 |
|
|
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 09:33:14 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 404464760DF; Wed, 9 Oct 2002 09:33:04 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP |
| id 42696476082; Wed, 9 Oct 2002 09:32:59 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g99DWphR019698; |
| Wed, 9 Oct 2002 09:32:51 -0400 (EDT) |
| To: Manfred Koizar <mkoi-pg@aon.at> |
| Cc: shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| In-reply-to: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
| References: <3D9C3E05.7070906@clearmetrix.com> |
| <3DA1A331.21316.F7E742B@localhost> |
| <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
| Comments: In-reply-to Manfred Koizar <mkoi-pg@aon.at> |
| message dated "Wed, 09 Oct 2002 10:00:03 +0200" |
| Date: Wed, 09 Oct 2002 09:32:50 -0400 |
| Message-ID: <19697.1034170370@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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|
|
| Manfred Koizar <mkoi-pg@aon.at> writes: |
| > here is an implementation of a set of user types: char3, char4, |
| > char10. |
|
|
| Coupla quick comments on these: |
|
|
| > CREATE FUNCTION charNN_lt(charNN, charNN) |
| > RETURNS boolean |
| > AS '$libdir/fixchar' |
| > LANGUAGE 'c'; |
|
|
| > bool |
| > charNN_lt(char *a, char *b) |
| > { |
| > return (strncmp(a, b, NN) < 0); |
| > } |
|
|
| These functions are dangerous as written, because they will crash on |
| null inputs. I'd suggest marking them strict in the function |
| declarations. Some attention to volatility declarations (isCachable |
| or isImmutable) would be a good idea too. |
| |
| Also, it'd be faster and more portable to write the functions with |
| version-1 calling conventions. |
|
|
| Using the Makefile to auto-create the differently sized versions is |
| a slick trick... |
|
|
| regards, tom lane |
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 09:41:46 2002 |
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| Wed, 9 Oct 2002 19:10:39 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Date: Wed, 09 Oct 2002 19:11:09 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: [pgsql-performance] Large databases, performance |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA47F4D.12909.1AAA876E@localhost> |
| References: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
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|
|
| On 9 Oct 2002 at 9:32, Tom Lane wrote: |
|
|
| > Manfred Koizar <mkoi-pg@aon.at> writes: |
| > > here is an implementation of a set of user types: char3, char4, |
| > > char10. |
| > |
| > Coupla quick comments on these: |
| > |
| > > CREATE FUNCTION charNN_lt(charNN, charNN) |
| > > RETURNS boolean |
| > > AS '$libdir/fixchar' |
| > > LANGUAGE 'c'; |
| > |
| > > bool |
| > > charNN_lt(char *a, char *b) |
| > > { |
| > > return (strncmp(a, b, NN) < 0); |
| > > } |
| > |
| > These functions are dangerous as written, because they will crash on |
| > null inputs. I'd suggest marking them strict in the function |
| > declarations. Some attention to volatility declarations (isCachable |
| > or isImmutable) would be a good idea too. |
| |
| Let me add something. Using char* is bad idea. I had faced a situation recently |
| on HP-UX 11 that with a libc patch, isspace collapsed for char>127. Fix was to |
| use unsigned char. There are other places also where the input character is |
| used as index to an array internally and can cause weird behaviour for values |
| >127 |
| |
| I will apply both the correction here. Will post the final stuff soon. |
| |
| Bye |
| Shridhar |
| |
| -- |
| Hacker's Quicky |
| Chocolate Milk |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 10:01:56 2002 |
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| id TK2FX4X1; Wed, 9 Oct 2002 10:01:51 -0400 |
| Subject: Re: What does this tell me? |
| From: Robert Treat <xzilla@users.sourceforge.net> |
| To: Josh Berkus <josh@agliodbs.com> |
| Cc: Joe Conway <mail@joeconway.com>, Bruce Momjian <pgman@candle.pha.pa.us>, |
| Sean Chittenden <sean@chittenden.org>, pgsql-performance@postgresql.org |
| In-Reply-To: <web-1776618@davinci.ethosmedia.com> |
| References: <web-1776618@davinci.ethosmedia.com> |
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|
|
| On Wed, 2002-10-09 at 01:22, Josh Berkus wrote: |
| > Joe, |
| > |
| > > If that's the case, can you split the work up into multiple |
| > > functions, and execute them all from a shell script? Or perhaps even |
| > > offload some of the data massaging to perl or something? (It would be |
| > > easier to recommend alternate approaches with more details.) |
| > |
| > I've already split it up into 11 functions, which are being managed |
| > through Perl with ANALYZE statements between. Breaking it down |
| > further would be really unmanageable. |
| > |
|
|
| If I read Tom's suggestion correctly, you should probably change these |
| to vacuum analyze instead of analyze. |
| |
| > Not to be mean or anything (after all, I just joined pgsql-advocacy), |
| > I'm getting *much* worse performance on large data transformations from |
| > PostgreSQL 7.2.1, than I get from SQL Server 7.0 on inferior hardware |
| > (at least, except where SQL Server 7.0 crashes). |
|
|
| what?? that's blasphamy!! revoke this mans advocacy membership right |
| now!! ;-) |
| |
| |
| I really am determined |
| > to prove that it's because I've misconfigured it, and I thank all of |
| > you for your help in doing so. |
| > |
| |
| FWIW I just ran into a similar situation where I was doing 6 |
| simultaneous pg_restores of our production database on my local |
| workstation. Apparently this pumps a lot of data through the wal logs. |
| I did kick up the number of wal files, but I also ended up kicking up |
| the number of wal_buffers as well and that seemed to help. |
| |
| Robert Treat |
| |
| |
| |
| From pgsql-general-owner@postgresql.org Wed Oct 9 12:57:16 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 71E7F47688D; Wed, 9 Oct 2002 12:57:14 -0400 (EDT) |
| Received: from aquilandia.com (unknown [195.55.211.234]) |
| by postgresql.org (Postfix) with ESMTP |
| id AD2FF4765B3; Wed, 9 Oct 2002 12:57:09 -0400 (EDT) |
| Received: from leo [213.97.49.3] by aquilandia.com |
| (SMTPD32-6.06) id A27C3A3C005E; Wed, 09 Oct 2002 19:08:12 +0200 |
| From: "Jose Antonio Leo" <jaleo8@storelandia.com> |
| To: <pgsql-general@postgresql.org>, <pgsql-sql@postgresql.org> |
| Subject: problem with the Index |
| Date: Wed, 9 Oct 2002 18:56:41 +0200 |
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| |
| I have a problem with the index of 1 table. |
| |
| I hava a table created : |
| CREATE TABLE "acucliart" ( |
| "cod_pto" numeric(8,0) NOT NULL, |
| "cod_cli" varchar(9) NOT NULL, |
| "mes" numeric(2,0) NOT NULL, |
| "ano" numeric(4,0) NOT NULL, |
| "int_art" numeric(5,0) NOT NULL, |
| "cantidad" numeric(12,2), |
| "ven_siv_to" numeric(14,2), |
| "ven_civ_to" numeric(14,2), |
| "tic_siv_to" numeric(14,2), |
| "tic_civ_to" numeric(14,2), |
| "visitas" numeric(2,0), |
| "ult_vis" date, |
| "ven_cos" numeric(12,2), |
| "ven_ofe" numeric(12,2), |
| "cos_ofe" numeric(12,2), |
| CONSTRAINT "acucliart_pkey" |
| PRIMARY KEY ("cod_cli") |
| ); |
| |
| if i do this select: |
| explain select * from acucliart where cod_cli=10000; |
| postgres use the index |
| NOTICE: QUERY PLAN: |
| Index Scan using cod_cli_ukey on acucliart (cost=0.00..4.82 rows=1 |
| width=478) |
| |
| and this select |
| explain select * from acucliart where cod_cli>10000; |
| Postgres don't use the index: |
| NOTICE: QUERY PLAN: |
| Seq Scan on acucliart (cost=0.00..22.50 rows=333 width=478) |
|
|
| why? |
|
|
|
|
| tk |
|
|
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 13:31:14 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
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| Date: Wed, 9 Oct 2002 10:31:12 -0700 (PDT) |
| From: Stephan Szabo <sszabo@megazone23.bigpanda.com> |
| To: Jose Antonio Leo <jaleo8@storelandia.com> |
| Cc: <pgsql-general@postgresql.org>, <pgsql-sql@postgresql.org> |
| Subject: Re: [SQL] problem with the Index |
| In-Reply-To: <AEEGKNMMPPBJJDLEJDODEEEMCJAA.jaleo8@storelandia.com> |
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|
|
| On Wed, 9 Oct 2002, Jose Antonio Leo wrote: |
|
|
| > I have a problem with the index of 1 table. |
| > |
| > I hava a table created : |
| > CREATE TABLE "acucliart" ( |
| > "cod_pto" numeric(8,0) NOT NULL, |
| > "cod_cli" varchar(9) NOT NULL, |
| > "mes" numeric(2,0) NOT NULL, |
| > "ano" numeric(4,0) NOT NULL, |
| > "int_art" numeric(5,0) NOT NULL, |
| > "cantidad" numeric(12,2), |
| > "ven_siv_to" numeric(14,2), |
| > "ven_civ_to" numeric(14,2), |
| > "tic_siv_to" numeric(14,2), |
| > "tic_civ_to" numeric(14,2), |
| > "visitas" numeric(2,0), |
| > "ult_vis" date, |
| > "ven_cos" numeric(12,2), |
| > "ven_ofe" numeric(12,2), |
| > "cos_ofe" numeric(12,2), |
| > CONSTRAINT "acucliart_pkey" |
| > PRIMARY KEY ("cod_cli") |
| > ); |
| > |
| > if i do this select: |
| > explain select * from acucliart where cod_cli=10000; |
| > postgres use the index |
| > NOTICE: QUERY PLAN: |
| > Index Scan using cod_cli_ukey on acucliart (cost=0.00..4.82 rows=1 |
| > width=478) |
| > |
| > and this select |
| > explain select * from acucliart where cod_cli>10000; |
| > Postgres don't use the index: |
| > NOTICE: QUERY PLAN: |
| > Seq Scan on acucliart (cost=0.00..22.50 rows=333 width=478) |
| > |
| > why? |
| |
| Well, how many rows are in the table? In the first case it estimates 1 |
| row will be returned, in the second 333. Index scans are not always faster |
| than sequential scans as the percentage of the table to scan becomes |
| larger. If you haven't analyzed recently, you probably should do so and |
| if you want to compare, set enable_seqscan=off and try an explain there |
| and see what it gives you. |
|
|
| Also, why are you comparing a varchar(9) column with an integer? |
|
|
|
|
| From pgsql-general-owner@postgresql.org Wed Oct 9 14:06:28 2002 |
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| for <tgl@sss.pgh.pa.us>; 9 Oct 2002 18:06:25 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Cc: shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org, |
| pgsql-general <pgsql-general@postgresql.org>, |
| pgsql-performance@postgresql.org |
| Subject: Re: [pgsql-performance] Large databases, performance |
| Date: Wed, 09 Oct 2002 20:09:03 +0200 |
| Message-ID: <hnf8quog5p54tf4tu0i12v00bc6bc9h0f2@4ax.com> |
| References: <3D9C3E05.7070906@clearmetrix.com> |
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|
|
| On Wed, 09 Oct 2002 09:32:50 -0400, Tom Lane <tgl@sss.pgh.pa.us> |
| wrote: |
| >Coupla quick comments on these: |
|
|
| My first attempt on user types; thanks for the tips. |
|
|
| >These functions are dangerous as written, because they will crash on |
| >null inputs. I'd suggest marking them strict in the function |
| >declarations. |
| |
| I was not aware of this, just wondered why bpchar routines didn't |
| crash :-) Fixed. |
|
|
| >Some attention to volatility declarations (isCachable |
| >or isImmutable) would be a good idea too. |
| >Also, it'd be faster and more portable to write the functions with |
| >version-1 calling conventions. |
| |
| Done, too. In the meantime I've found out why it crashed with 7.3: |
| INSERT INTO pg_opclass is now obsolete, have to use CREATE OPERATOR |
| CLASS ... |
|
|
| Servus |
| Manfred |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 9 15:32:31 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id D73964762B6 |
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|
| From pgsql-performance-owner@postgresql.org Thu Oct 10 09:27:59 2002 |
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| Thu, 10 Oct 2002 09:27:56 -0400 (EDT) |
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| Thu, 10 Oct 2002 09:27:48 -0400 (EDT) |
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| for <shridhar?daithankar@persistent.co.in>; 10 Oct 2002 13:27:50 -0000 |
| From: Manfred Koizar <mkoi-pg@aon.at> |
| To: shridhar_daithankar@persistent.co.in |
| Cc: pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org |
| Subject: contrib/fixchar (Was: Large databases, performance) |
| Date: Thu, 10 Oct 2002 15:30:31 +0200 |
| Message-ID: <aeuaqu8uk5qi6ledajbu8a0kqk2m2c6m3u@4ax.com> |
| References: <3D9C3E05.7070906@clearmetrix.com> |
| <3DA1A331.21316.F7E742B@localhost> |
| <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> |
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|
|
| On Wed, 09 Oct 2002 10:00:03 +0200, I wrote: |
| >here is an implementation of a set of user types: char3, char4, |
| >char10. |
|
|
| New version available. As I don't want to spam the list with various |
| versions until I get it right eventually, you can get it from |
| http://members.aon.at/pivot/pg/fixchar20021010.tgz if you are |
| interested. |
| |
| What's new: |
|
|
| . README updated (per Shridhar's suggestion) |
| . doesn't crash on NULL (p. Tom) |
| . version-1 calling conventions (p. Tom) |
| . isCachable (p. Tom) |
| . works for 7.2 (as delivered) and for 7.3 (make for73) |
|
|
| Shridhar, you were concerned about signed/unsigned chars; looking at |
| the code I can not see how this is a problem. So no change in this |
| regard. |
|
|
| Thanks for your comments. Have fun! |
|
|
| Servus |
| Manfred |
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 10 09:48:43 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-performance@postgresql.org>; Thu, 10 Oct 2002 19:18:42 +0530 |
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| Thu, 10 Oct 2002 19:18:42 +0530 |
| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org |
| Date: Thu, 10 Oct 2002 19:19:11 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: contrib/fixchar (Was: Large databases, performance) |
| Reply-To: shridhar_daithankar@persistent.co.in |
| Message-ID: <3DA5D2AF.24682.4EDF20B@localhost> |
| In-reply-to: <aeuaqu8uk5qi6ledajbu8a0kqk2m2c6m3u@4ax.com> |
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|
|
| On 10 Oct 2002 at 15:30, Manfred Koizar wrote: |
|
|
| > On Wed, 09 Oct 2002 10:00:03 +0200, I wrote: |
| > >here is an implementation of a set of user types: char3, char4, |
| > >char10. |
| > |
| > New version available. As I don't want to spam the list with various |
| > versions until I get it right eventually, you can get it from |
| > http://members.aon.at/pivot/pg/fixchar20021010.tgz if you are |
| > interested. |
| > |
| > What's new: |
| > |
| > . README updated (per Shridhar's suggestion) |
| > . doesn't crash on NULL (p. Tom) |
| > . version-1 calling conventions (p. Tom) |
| > . isCachable (p. Tom) |
| > . works for 7.2 (as delivered) and for 7.3 (make for73) |
| > |
| > Shridhar, you were concerned about signed/unsigned chars; looking at |
| > the code I can not see how this is a problem. So no change in this |
| > regard. |
|
|
| Well, this is not related to postgresql exactly but to summerise the problem, |
| with libc patch PHCO_19090 or compatible upwards, on HP-UX11, isspace does not |
| work correctly if input value is >127. Can cause lot of problem for an external |
| app. It works fine with unsigned char |
|
|
| Does not make a difference from postgrersql point of view but would break non- |
| english locale if they want to use this fix under some situation. |
|
|
| But I agree, unless somebody reports it, no point fixing it and we know the fix |
| anyway.. |
|
|
|
|
| Bye |
| Shridhar |
|
|
| |
| Live long and prosper. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 10 11:42:12 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 9D22A476AB3 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 10 Oct 2002 11:42:11 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id D4254476AA9 |
| for <pgsql-performance@postgresql.org>; |
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| for pgsql-performance@postgresql.org; Thu, 10 Oct 2002 16:38:21 +0100 |
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| pgsql-performance@postgresql.org; Thu, 10 Oct 2002 16:41:36 +0100 (BST) |
| Date: Thu, 10 Oct 2002 16:41:43 +0100 |
| From: Adam Witney <awitney@sghms.ac.uk> |
| To: pgsql-performance <pgsql-performance@postgresql.org> |
| Message-id: <B9CB5E47.949D%a.witney@sghms.ac.uk> |
| MIME-version: 1.0 |
| User-Agent: Microsoft-Entourage/10.1.0.2006 |
| Subject: Info on explain output |
| Content-type: text/plain; charset=US-ASCII |
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| tests=TO_LOCALPART_EQ_REAL,USER_IN_WHITELIST version=2.31 |
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|
|
| Hi, |
|
|
| I am trying to optimise a complex query adding explicit joins and creating |
| indices. I am going through the EXPLAIN output (~70 lines) but am fairly new |
| at reading these. |
|
|
| Are there any good rules of thumb of things one should be looking out for in |
| EXPLAIN output? ie <blah> means that an index would be good here etc |
|
|
| I have read through the docs for EXPLAIN, but I was wondering if there were |
| any more detailed descriptions or docs on the subject. |
|
|
| Thanks for any help |
|
|
| adam |
|
|
|
|
| |
| This message has been scanned for viruses and |
| dangerous content by MailScanner, and is |
| believed to be clean. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 10 12:44:12 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1E007476112 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 10 Oct 2002 12:44:11 -0400 (EDT) |
| Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) |
| by postgresql.org (Postfix) with ESMTP id 79A2F47600C |
| for <pgsql-performance@postgresql.org>; |
| Thu, 10 Oct 2002 12:44:08 -0400 (EDT) |
| Received: (from pgman@localhost) |
| by candle.pha.pa.us (8.11.6/8.10.1) id g9AGi1F17476; |
| Thu, 10 Oct 2002 12:44:01 -0400 (EDT) |
| From: Bruce Momjian <pgman@candle.pha.pa.us> |
| Message-Id: <200210101644.g9AGi1F17476@candle.pha.pa.us> |
| Subject: Re: Info on explain output |
| In-Reply-To: <B9CB5E47.949D%a.witney@sghms.ac.uk> |
| To: Adam Witney <awitney@sghms.ac.uk> |
| Date: Thu, 10 Oct 2002 12:44:01 -0400 (EDT) |
| Cc: pgsql-performance <pgsql-performance@postgresql.org> |
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|
|
|
|
| Have you looked at the internals PDF at the bottom of the developers |
| lounge web page? |
|
|
| |
|
|
| Adam Witney wrote: |
| > Hi, |
| > |
| > I am trying to optimise a complex query adding explicit joins and creating |
| > indices. I am going through the EXPLAIN output (~70 lines) but am fairly new |
| > at reading these. |
| > |
| > Are there any good rules of thumb of things one should be looking out for in |
| > EXPLAIN output? ie <blah> means that an index would be good here etc |
| > |
| > I have read through the docs for EXPLAIN, but I was wondering if there were |
| > any more detailed descriptions or docs on the subject. |
| > |
| > Thanks for any help |
| > |
| > adam |
| > |
| > |
| > |
| > This message has been scanned for viruses and |
| > dangerous content by MailScanner, and is |
| > believed to be clean. |
| > |
| > |
| > |
| > TIP 6: Have you searched our list archives? |
| > |
| > http://archives.postgresql.org |
| > |
|
|
| |
| Bruce Momjian | http://candle.pha.pa.us |
| pgman@candle.pha.pa.us | (610) 359-1001 |
| + If your life is a hard drive, | 13 Roberts Road |
| + Christ can be your backup. | Newtown Square, Pennsylvania 19073 |
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 10 12:59:20 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 03F4F475D0D |
| for <pgsql-performance@postgresql.org>; |
| Thu, 10 Oct 2002 12:59:19 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id 67C10475CA9 |
| for <pgsql-performance@postgresql.org>; |
| Thu, 10 Oct 2002 12:59:18 -0400 (EDT) |
| Received: from [216.135.165.74] (account <josh@agliodbs.com>) |
| by davinci.ethosmedia.com (CommuniGate Pro WebUser 3.5.9) |
| with HTTP id 1780475; Thu, 10 Oct 2002 09:59:18 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Info on explain output |
| To: Bruce Momjian <pgman@candle.pha.pa.us>, Adam Witney <awitney@sghms.ac.uk> |
| Cc: pgsql-performance <pgsql-performance@postgresql.org> |
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|
|
| Adam, |
|
|
| > > Are there any good rules of thumb of things one should be looking |
| > out for in |
| > > EXPLAIN output? ie <blah> means that an index would be good here |
| > etc |
|
|
| Also try: |
| 1) Various articles on Techdocs.postgresql.org |
| 2) Ewald G.'s PostgreSQL Book |
| |
| Explain output is not that easily converted into a plan of action ... |
| otherwise, Postgres would have automated it, neh? You have to get a |
| feel for what looks good and bad dynamically. |
| |
| -Josh Berkus |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 11 03:14:49 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 872C947590C; Fri, 11 Oct 2002 03:14:46 -0400 (EDT) |
| Received: from relay.icomedias.com (relay.icomedias.com [62.99.232.66]) |
| by postgresql.org (Postfix) with ESMTP |
| id 3499A474E5C; Fri, 11 Oct 2002 03:14:45 -0400 (EDT) |
| Received: from 10.192.17.128 ([10.192.17.128]) |
| by relay.icomedias.com (8.12.5/8.12.5) with ESMTP id g9B7Egcj021890; |
| Fri, 11 Oct 2002 09:14:43 +0200 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Mario Weilguni <mweilguni@sime.com> |
| To: pgsql-performance@postgresql.org |
| Subject: number of attributes in page files? |
| Date: Fri, 11 Oct 2002 09:14:50 +0200 |
| User-Agent: KMail/1.4.3 |
| Cc: pgsql-hackers@postgresql.org |
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| |
| Is it possible to get rid of the "t_natts" fields in the tuple header? Is t= |
| his field only for "alter table add/drop" support? Then it might |
| possible to get rid of it and put the "t_natts" field in the page header, n= |
| ot the tuple header, if it can be assured that when updating/inserting |
| records only a compatible (a page file with the same number of attributes) = |
| page file is used. Especially master-detail tables would=20 |
| profit from this, reducing the tuple overhead by another 9%. |
| |
| Might this be possible? |
| |
| Regards, |
| Mario Weilguni |
| |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 11 04:43:59 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-performance@postgresql.org>; |
| Fri, 11 Oct 2002 04:43:57 -0400 (EDT) |
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| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Mario Weilguni <mweilguni@sime.com> |
| To: pgsql-performance@postgresql.org |
| Subject: Compile test with gcc 3.2 |
| Date: Fri, 11 Oct 2002 10:44:03 +0200 |
| User-Agent: KMail/1.4.3 |
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| |
| If you want to get the max (CPU) performance and use gcc, you should give t= |
| he -fprofile-arcs / -fbranch-probabilties options of gcc 3.2 a try.=20 |
| For 50 pgbench read-only runs (1 mio tuples, 40000 txs, 10 clients) I get 1= |
| 4.4% speedup.=20 |
| |
| Then I tried it with real data from our production system. |
| This is 2GB data, 120 tables, but most of the data is large object data (1.= |
| 8GB), so most tables of the database are in-memory and the application is = |
| more cpu bound. |
| With this scenario, I still get 8% improvement.=20 |
| |
| All tests done on an Athlon XP/1500, 768MB RAM, Linux 2.4.19, gcc 3.2, 5400= |
| RPM Maxtor. |
| |
| Might be worth a try. Probably the performance win will be smaller for larg= |
| er databases. |
| |
| Regards, |
| Mario Weilguni |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 11 08:12:54 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP |
| id 2D8F44766CB; Fri, 11 Oct 2002 08:12:49 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP |
| id 4829D47675B; Fri, 11 Oct 2002 08:12:48 -0400 (EDT) |
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| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g9BCCohR004296; |
| Fri, 11 Oct 2002 08:12:51 -0400 (EDT) |
| To: Mario Weilguni <mweilguni@sime.com> |
| Cc: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org |
| Subject: Re: [HACKERS] number of attributes in page files? |
| In-reply-to: <200210110914.50377.mweilguni@sime.com> |
| References: <200210110914.50377.mweilguni@sime.com> |
| Comments: In-reply-to Mario Weilguni <mweilguni@sime.com> |
| message dated "Fri, 11 Oct 2002 09:14:50 +0200" |
| Date: Fri, 11 Oct 2002 08:12:50 -0400 |
| Message-ID: <4295.1034338370@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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| X-Archive-Number: 200210/96 |
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| |
| Mario Weilguni <mweilguni@sime.com> writes: |
| > Is it possible to get rid of the "t_natts" fields in the tuple header? |
| > Is this field only for "alter table add/drop" support? |
| |
| "Only"? A lot of people consider that pretty important ... |
| |
| But removing 2 bytes isn't going to save anything, on most machines, |
| because of alignment considerations. |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Fri Oct 11 10:00:08 2002 |
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| From: Mario Weilguni <mweilguni@sime.com> |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Subject: Re: [HACKERS] number of attributes in page files? |
| Date: Fri, 11 Oct 2002 16:00:13 +0200 |
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| Cc: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org |
| References: <200210110914.50377.mweilguni@sime.com> |
| <4295.1034338370@sss.pgh.pa.us> |
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|
|
| Am Freitag, 11. Oktober 2002 14:12 schrieb Tom Lane: |
| > Mario Weilguni <mweilguni@sime.com> writes: |
| > > Is it possible to get rid of the "t_natts" fields in the tuple header? |
| > > Is this field only for "alter table add/drop" support? |
| > |
| > "Only"? A lot of people consider that pretty important ... |
|
|
| With "only" I mean it's an administrative task which requires operator inte= |
| rvenation anyways, and it's a seldom needed operation which may take longer= |
| , when |
| queries become faster. |
|
|
| > |
| > But removing 2 bytes isn't going to save anything, on most machines, |
| > because of alignment considerations. |
| |
| ok, I did not consider alignment, but the question remains, is this easily = |
| doable? Especially because only one another byte has to be saved for |
| real saving on many architectures, which is t_hoff. IMO t_hoff is not usefu= |
| l because it can be computed easily. This would give 20 byte headers instea= |
| d of 23 (24) bytes as it's now.=20 |
| This is 17% saved, and if it's not too complicated it might be worth to con= |
| sider. |
| |
| Best regards, |
| Mario Weilguni |
| |
| From pgsql-performance-owner@postgresql.org Fri Oct 11 10:34:56 2002 |
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| Fri, 11 Oct 2002 07:34:58 PDT |
| Date: Fri, 11 Oct 2002 07:34:58 -0700 (PDT) |
| From: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Subject: Re: Compile test with gcc 3.2 |
| To: Mario Weilguni <mweilguni@sime.com> |
| Cc: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| In-Reply-To: <200210111044.03361.mweilguni@sime.com> |
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| |
| Hi Mario: |
| --- Mario Weilguni <mweilguni@sime.com> wrote: |
| > If you want to get the max (CPU) performance and use |
| > gcc, you should give the -fprofile-arcs / |
| > -fbranch-probabilties options of gcc 3.2 a try. |
| > For 50 pgbench read-only runs (1 mio tuples, 40000 |
| > txs, 10 clients) I get 14.4% speedup. |
| > |
| > Then I tried it with real data from our production |
| > system. |
| > This is 2GB data, 120 tables, but most of the data |
| > is large object data (1.8GB), so most tables of the |
| > database are in-memory and the application is more |
| > cpu bound. |
| > With this scenario, I still get 8% improvement. |
| > |
| > All tests done on an Athlon XP/1500, 768MB RAM, |
| > Linux 2.4.19, gcc 3.2, 5400 RPM Maxtor. |
| > |
| > Might be worth a try. Probably the performance win |
| > will be smaller for larger databases. |
| |
| - Do you use the "-fprofile-arcs |
| -fbranch-probabilties" options with other optimization |
| flags? I've in a book (Optimimizing Red Hat Linux 6.2) |
| that one could also optimize speed by setting the |
| CFLAGS to the following : |
| " -02 -fomit-frame-pointers -funroll-loops" and |
| running "strip" on the on binaries after they are |
| compiled. |
|
|
| regards, |
| ludwig. |
|
|
| __________________________________________________ |
| Do you Yahoo!? |
| New DSL Internet Access from SBC & Yahoo! |
| http://sbc.yahoo.com |
|
|
| From pgsql-performance-owner@postgresql.org Fri Oct 11 12:01:40 2002 |
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| Reply-To: "Waruna Geekiyanage" <waruna@nirmani.com> |
| From: "Waruna Geekiyanage" <waruna@nirmani.com> |
| To: <pgsql-php@postgresql.org> |
| Cc: <pgsql-performance@postgresql.org> |
| Subject: syncronize databases |
| Date: Fri, 11 Oct 2002 22:02:31 +0600 |
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| |
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|
| I need to syncronize two pgsql databases runing on RedHat linux7.2. |
| One is on our LAN and other one on the internet which we connect through a = |
| dialup connection. |
|
|
| Waruna |
|
|
| |
| Content-Type: text/html; |
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| <DIV><FONT face=3DArial size=3D2>I need to syncronize two pgsql databases r= |
| uning on=20 |
| RedHat linux7.2.</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2>One is on our LAN and other one on the int= |
| ernet=20 |
| which we connect through a dialup connection.</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV> |
| <DIV><FONT face=3DArial size=3D2>Waruna</FONT></DIV></BODY></HTML> |
|
|
| |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Fri Oct 11 15:23:56 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id F0A434768C1 |
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| Fri, 11 Oct 2002 15:23:55 -0400 (EDT) |
| Received: from absinthe.carnagecopia.com (absinthe.carnagecopia.com |
| [216.187.87.246]) |
| by postgresql.org (Postfix) with SMTP id 1DBE247668C |
| for <pgsql-performance@postgresql.org>; |
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| Date: Fri, 11 Oct 2002 15:24:29 -0400 |
| From: Vincent Janelle <random@goblinstudios.com> |
| To: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Cc: mweilguni@sime.com, pgsql-performance@postgresql.org |
| Subject: Re: Compile test with gcc 3.2 |
| Message-Id: <20021011152429.6ef918d1.random@goblinstudios.com> |
| In-Reply-To: <20021011143458.48739.qmail@web80307.mail.yahoo.com> |
| References: <200210111044.03361.mweilguni@sime.com> |
| <20021011143458.48739.qmail@web80307.mail.yahoo.com> |
| Organization: http://www.goblinstudios.com/ |
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|
|
| except when you run the regression tests you get some very interesting results. |
|
|
| On Fri, 11 Oct 2002 07:34:58 -0700 (PDT) |
| Ludwig Lim <lud_nowhere_man@yahoo.com> wrote: |
|
|
| > |
| > - Do you use the "-fprofile-arcs |
| > -fbranch-probabilties" options with other optimization |
| > flags? I've in a book (Optimimizing Red Hat Linux 6.2) |
| > that one could also optimize speed by setting the |
| > CFLAGS to the following : |
| > " -02 -fomit-frame-pointers -funroll-loops" and |
| > running "strip" on the on binaries after they are |
| > compiled. |
| > |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 16 14:02:25 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 8B0F3475E8A |
| for <pgsql-performance@postgresql.org>; |
| Wed, 16 Oct 2002 14:02:22 -0400 (EDT) |
| Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250]) |
| by postgresql.org (Postfix) with ESMTP id EA7F8475DF2 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 16 Oct 2002 14:02:21 -0400 (EDT) |
| Received: from [66.219.92.2] (HELO chocolate-mousse) |
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| with ESMTP id 1788844 for pgsql-performance@postgresql.org; |
| Wed, 16 Oct 2002 11:02:59 -0700 |
| Content-Type: text/plain; |
| charset="us-ascii" |
| From: Josh Berkus <josh@agliodbs.com> |
| Reply-To: josh@agliodbs.com |
| Organization: Aglio Database Solutions |
| To: pgsql-performance@postgresql.org |
| Subject: PG_Autotune 0.1 |
| Date: Tue, 15 Oct 2002 11:00:58 -0700 |
| X-Mailer: KMail [version 1.4] |
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| |
| Folks, Justin, |
| |
| Hey, I've been tinkering with PG_autotune in an effort to make it usable on= |
| my=20 |
| installation.=20=20=20 |
| http://gborg.postgresql.org/project/pgautotune/projdisplay.php |
|
|
| First off, thank you Justin for getting inspired and writing the starter=20 |
| version. This is something that would probably have remained *way* down t= |
| he=20 |
| Postgres TODO list, were it not for you.=20 |
|
|
| Since it's such a great idea, I'd like to make it bulletproof so that it ca= |
| n=20 |
| become part of the standard Postgres distribution. I'm hoping that people= |
| =20 |
| on this list can help. |
| |
| Problems, Bugs, & Suggestions: |
| 1) The program makes the assumption that the Postgres superuser is named=20 |
| "pgsql", forcing me to do a search-and-replace on the source to make it wor= |
| k=20 |
| at all on my system, where the superuser is named "postgres". This should= |
| =20 |
| be a configuration option. Places I've identified where this is an issue:= |
| =20=20 |
| a. the connection to the "metrics" database, b. the calls to Postgres=20 |
| executables (which are also sometimes made as the console user, causing the= |
| m=20 |
| to fail if you run the program as "root"). |
|
|
| 2) The program also assumes that all Postgres binaries are symlinked in=20 |
| /usr/local/bin. Since this symlinking isn't done by Postgres-make-instal= |
| l,=20 |
| wouldn't it be better to reference $PGHOME/bin?=20=20=20 |
|
|
| 3) For that matter, it would be nice if the program would test $PGDATA and= |
| =20 |
| $PGHOME, and prompt the user if they are empty. |
|
|
| 4) The shell scripts need to have error-checking so that they exit if anyth= |
| ing=20 |
| blows up. I can write this if Justin can explain what the shell scripts a= |
| re=20 |
| supposed to do, exactly, and where errors are acceptable. |
|
|
| 5) We need installation docs. I can write these. Sometime soon, really! |
|
|
| Questions & Suggestions for Enhancement: |
|
|
| 6) The shared_buffers param is capped at 500. Isn't this awfully low for a= |
| =20 |
| production server? What's the logic here? |
|
|
| 7) Any ideas on how to get around/adjust memory maximums for the host OS?= |
| =20=20 |
| This is easy on Linux, but other *nixes are not so easy. |
|
|
| 8) What will be the difficulties in expanding the script to adjust more=20 |
| Postgresql.conf params, such as checkpoint_segments? Can we use feedback= |
| =20 |
| from the log to adjust these? |
|
|
| 9) I *love* the idea of letting the benchmarking script run custom queries.= |
| =20=20=20 |
| However, I would dearly like to expand it, letting it randomly grab from a= |
| =20 |
| list of 10 custom queries entered by the user into a file or files. This= |
| =20 |
| would allow the user to create a realistic mix of simple and complex querie= |
| s,=20 |
| including some data manipulation and procedures. |
|
|
| 10) Can we eventually adjust the program to get feedback from system tools = |
| and=20 |
| give the user hints on hardware limitations? For example, have the program= |
| =20 |
| test if, at maximum settings, queries are slow but CPU and RAM are only 10%= |
| =20 |
| utilized and tell the user "Your hard drives are probably too slow"? |
|
|
| I can help with: documentation, shell scripting, Linux system issues. Oth= |
| er=20 |
| volunteers to help? |
|
|
| |
| -Josh Berkus |
| Aglio Database Solutions |
| San Francisco |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 17 10:44:57 2002 |
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| Thu, 17 Oct 2002 10:44:53 -0400 (EDT) |
| Received: from chad [63.230.8.76] by utahisp.com |
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| Message-ID: <068c01c275eb$c9ba4f70$32021aac@chad> |
| From: "Chad Thompson" <chad@weblinkservices.com> |
| To: "pgsql-performance" <pgsql-performance@postgresql.org> |
| Subject: Max time queries |
| Date: Thu, 17 Oct 2002 08:45:07 -0600 |
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| Heres an oddity. Why would it take more time to not find an answer than it= |
| would to find one?=20=20 |
| Here are my 2 queries. |
| The Cold Fusion output of the query is followed by an explain analyze. |
|
|
| maxTime (Records=3D0, Time=3D2223ms) |
| SQL =3D=20 |
| select cr.start_time as max |
| from call_results cr, timezone tz, lists l |
| where (cr.start_time between '10/15/2002 08:00' and '10/15/2002 23:00') |
| and l.full_phone =3D cr.phonenum |
| and l.area_code =3D tz.area_code |
| and tz.greenwich =3D '-7' |
| and cr.project_id =3D 11 |
| and l.client_id =3D 8=20 |
| order by cr.start_time desc |
| limit 1 |
|
|
| NOTICE: QUERY PLAN: |
|
|
| Limit (cost=3D0.00..1544.78 rows=3D1 width=3D49) (actual time=3D2299.11..2= |
| 299.11 rows=3D0 loops=3D1) |
| -> Nested Loop (cost=3D0.00..1266550.38 rows=3D820 width=3D49) (actual = |
| time=3D2299.10..2299.10 rows=3D0 loops=3D1) |
| -> Nested Loop (cost=3D0.00..776978.04 rows=3D90825 width=3D42) (= |
| actual time=3D0.84..1849.97 rows=3D9939 loops=3D1) |
| -> Index Scan Backward using start_time_idx on call_results = |
| cr (cost=3D0.00..6569.39 rows=3D6693 width=3D22) (actual time=3D0.38..303.= |
| 58 rows=3D9043 loops=3D1) |
| -> Index Scan using full_phone_idx on lists l (cost=3D0.00.= |
| .114.94 rows=3D14 width=3D20) (actual time=3D0.15..0.16 rows=3D1 loops=3D90= |
| 43) |
| -> Index Scan using area_code_idx on timezone tz (cost=3D0.00..5.= |
| 38 rows=3D1 width=3D7) (actual time=3D0.04..0.04 rows=3D0 loops=3D9939) |
| Total runtime: 2300.55 msec |
|
|
|
|
| maxTime (Records=3D1, Time=3D10ms) |
| SQL =3D=20 |
| select cr.start_time as max |
| from call_results cr, timezone tz, lists l |
| where (cr.start_time between '10/15/2002 08:00' and '10/15/2002 23:00') |
| and l.full_phone =3D cr.phonenum |
| and l.area_code =3D tz.area_code |
| and tz.greenwich =3D '-8' |
| and cr.project_id =3D 11 |
| and l.client_id =3D 8=20 |
| order by cr.start_time desc |
| limit 1 |
| NOTICE: QUERY PLAN: |
|
|
| Limit (cost=3D0.00..331.03 rows=3D1 width=3D49) (actual time=3D1.19..1.53 = |
| rows=3D1 loops=3D1) |
| -> Nested Loop (cost=3D0.00..1266550.38 rows=3D3826 width=3D49) (actual= |
| time=3D1.19..1.52 rows=3D2 loops=3D1) |
| -> Nested Loop (cost=3D0.00..776978.04 rows=3D90825 width=3D42) (= |
| actual time=3D0.84..1.10 rows=3D2 loops=3D1) |
| -> Index Scan Backward using start_time_idx on call_results = |
| cr (cost=3D0.00..6569.39 rows=3D6693 width=3D22) (actual time=3D0.39..0.48= |
| rows=3D2 loops=3D1) |
| -> Index Scan using full_phone_idx on lists l (cost=3D0.00.= |
| .114.94 rows=3D14 width=3D20) (actual time=3D0.30..0.30 rows=3D1 loops=3D2) |
| -> Index Scan using area_code_idx on timezone tz (cost=3D0.00..5.= |
| 38 rows=3D1 width=3D7) (actual time=3D0.19..0.20 rows=3D1 loops=3D2) |
| Total runtime: 1.74 msec |
|
|
|
|
| |
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| charset="iso-8859-1" |
| Content-Transfer-Encoding: quoted-printable |
|
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| <META content=3D"MSHTML 6.00.2719.2200" name=3DGENERATOR> |
| <STYLE></STYLE> |
| </HEAD> |
| <BODY bgColor=3D |
| <DIV>Heres an oddity. Why would it take more time to not find an answ= |
| er=20 |
| than it would to find one? </DIV> |
| <DIV><FONT face=3DArial size=3D2>Here are my 2 queries.</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2>The Cold Fusion output of the query is fol= |
| lowed by=20 |
| an explain analyze.</FONT></DIV> |
| <DIV><FONT face=3DArial size=3D2></FONT> </DIV> |
| <DIV><STRONG>maxTime</STRONG> (Records=3D0, Time=3D2223ms)<BR>SQL =3D <BR>s= |
| elect=20 |
| cr.start_time as max<BR> from call_results cr, timezone tz, lists=20 |
| l<BR> where (cr.start_time between '10/15/2002 08:00' and '10/15/2002=20 |
| 23:00')<BR> and l.full_phone =3D cr.phonenum<BR> and l.area_code =3D= |
| =20 |
| tz.area_code<BR> and tz.greenwich =3D '-7'<BR> and cr.project_id =3D= |
| =20 |
| 11<BR> and l.client_id =3D 8 <BR> order by cr.start_time desc<BR> = |
| limit=20 |
| 1</DIV> |
| <DIV> </DIV> |
| <DIV><FONT face=3DArial size=3D2>NOTICE: QUERY PLAN:</FONT></DIV> |
| <DIV> </DIV> |
| <DIV><FONT face=3DArial size=3D2>Limit (cost=3D0.00..1544.78 rows=3D1= |
| width=3D49)=20 |
| (actual time=3D2299.11..2299.11 rows=3D0 loops=3D1)<BR> -> N= |
| ested=20 |
| Loop (cost=3D0.00..1266550.38 rows=3D820 width=3D49) (actual=20 |
| time=3D2299.10..2299.10 rows=3D0=20 |
| loops=3D1)<BR> -> Nested= |
| =20 |
| Loop (cost=3D0.00..776978.04 rows=3D90825 width=3D42) (actual time=3D= |
| 0.84..1849.97=20 |
| rows=3D9939=20 |
| loops=3D1)<BR> &= |
| nbsp; =20 |
| -> Index Scan Backward using start_time_idx on call_results cr&nbs= |
| p;=20 |
| (cost=3D0.00..6569.39 rows=3D6693 width=3D22) (actual time=3D0.38..303.58 r= |
| ows=3D9043=20 |
| loops=3D1)<BR> &= |
| nbsp; =20 |
| -> Index Scan using full_phone_idx on lists l (cost=3D0.00..= |
| 114.94=20 |
| rows=3D14 width=3D20) (actual time=3D0.15..0.16 rows=3D1=20 |
| loops=3D9043)<BR> -> Ind= |
| ex Scan=20 |
| using area_code_idx on timezone tz (cost=3D0.00..5.38 rows=3D1 width= |
| =3D7)=20 |
| (actual time=3D0.04..0.04 rows=3D0 loops=3D9939)<BR>Total runtime: 2300.55= |
| =20 |
| msec<BR></FONT></DIV> |
| <DIV><BR><STRONG>maxTime</STRONG> (Records=3D1, Time=3D10ms)<BR>SQL =3D <BR= |
| >select=20 |
| cr.start_time as max<BR> from call_results cr, timezone tz, lists=20 |
| l<BR> where (cr.start_time between '10/15/2002 08:00' and '10/15/2002=20 |
| 23:00')<BR> and l.full_phone =3D cr.phonenum<BR> and l.area_code =3D= |
| =20 |
| tz.area_code<BR> and tz.greenwich =3D '-8'<BR> and cr.project_id =3D= |
| =20 |
| 11<BR> and l.client_id =3D 8 <BR> order by cr.start_time desc<BR> = |
| limit=20 |
| 1<BR> NOTICE: QUERY PLAN:</DIV> |
| <DIV> </DIV> |
| <DIV>Limit (cost=3D0.00..331.03 rows=3D1 width=3D49) (actual time=3D1= |
| .19..1.53=20 |
| rows=3D1 loops=3D1)<BR> -> Nested Loop (cost=3D0.00..1= |
| 266550.38=20 |
| rows=3D3826 width=3D49) (actual time=3D1.19..1.52 rows=3D2=20 |
| loops=3D1)<BR> -> Nested= |
| =20 |
| Loop (cost=3D0.00..776978.04 rows=3D90825 width=3D42) (actual time=3D= |
| 0.84..1.10=20 |
| rows=3D2=20 |
| loops=3D1)<BR> &= |
| nbsp; =20 |
| -> Index Scan Backward using start_time_idx on call_results cr&nbs= |
| p;=20 |
| (cost=3D0.00..6569.39 rows=3D6693 width=3D22) (actual time=3D0.39..0.48 row= |
| s=3D2=20 |
| loops=3D1)<BR> &= |
| nbsp; =20 |
| -> Index Scan using full_phone_idx on lists l (cost=3D0.00..= |
| 114.94=20 |
| rows=3D14 width=3D20) (actual time=3D0.30..0.30 rows=3D1=20 |
| loops=3D2)<BR> -> Index = |
| Scan=20 |
| using area_code_idx on timezone tz (cost=3D0.00..5.38 rows=3D1 width= |
| =3D7)=20 |
| (actual time=3D0.19..0.20 rows=3D1 loops=3D2)<BR>Total runtime: 1.74=20 |
| msec<BR></DIV></BODY></HTML> |
|
|
| |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Thu Oct 17 21:37:25 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id B9C6947687B |
| for <pgsql-performance@postgresql.org>; |
| Thu, 17 Oct 2002 21:37:24 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id E4C3A47687A |
| for <pgsql-performance@postgresql.org>; |
| Thu, 17 Oct 2002 21:37:23 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g9I1bRhR013381; |
| Thu, 17 Oct 2002 21:37:27 -0400 (EDT) |
| To: "Chad Thompson" <chad@weblinkservices.com> |
| Cc: "pgsql-performance" <pgsql-performance@postgresql.org> |
| Subject: Re: Max time queries |
| In-reply-to: <068c01c275eb$c9ba4f70$32021aac@chad> |
| References: <068c01c275eb$c9ba4f70$32021aac@chad> |
| Comments: In-reply-to "Chad Thompson" <chad@weblinkservices.com> |
| message dated "Thu, 17 Oct 2002 08:45:07 -0600" |
| Date: Thu, 17 Oct 2002 21:37:27 -0400 |
| Message-ID: <13380.1034905047@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/103 |
| X-Sequence-Number: 120 |
|
|
| "Chad Thompson" <chad@weblinkservices.com> writes: |
| > Heres an oddity. Why would it take more time to not find an answer than it |
| > would to find one? |
|
|
| Because the successful query stops as soon as it's exhausted the LIMIT |
| (ie, after it's found the first matching combination of rows). The |
| failing query has to run through the whole tables looking in vain for |
| a match. Note the difference in number of rows scanned in the lower |
| levels of your query. |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 21 02:23:35 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id C01EC475D00 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 02:23:33 -0400 (EDT) |
| Received: from relay.icomedias.com (relay.icomedias.com [62.99.232.66]) |
| by postgresql.org (Postfix) with ESMTP id 9D1DA475A9E |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 02:23:31 -0400 (EDT) |
| Received: from 10.192.17.128 ([10.192.17.128]) |
| by relay.icomedias.com (8.12.5/8.12.5) with ESMTP id g9L6NQcj021530 |
| for <pgsql-performance@postgresql.org>; Mon, 21 Oct 2002 08:23:27 +0200 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Mario Weilguni <mweilguni@sime.com> |
| To: pgsql-performance@postgresql.org |
| Subject: Self-generating statistics? |
| Date: Mon, 21 Oct 2002 08:23:33 +0200 |
| User-Agent: KMail/1.4.3 |
| MIME-Version: 1.0 |
| Content-Transfer-Encoding: quoted-printable |
| Message-Id: <200210210823.33744.mweilguni@sime.com> |
| avpresult: 0, ok, ok |
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| X-Sequence-Number: 121 |
|
|
| Something that might be worth considering: |
|
|
| Many of the performance problems on pgsql-general seem to be related to the= |
| fact that no analyze is performed after the creation on the tables, so |
| maybe this might be an option to fix that (in future releases): when a tabl= |
| e has no statistics at all, and the first seq-scan on the table is |
| performed, it might improve further performance if this seq-scan is used to= |
| get table statistics too. This should not be too expensive since reading t= |
| he |
| table has to be done only once. Further queries will have at least prelimin= |
| ary statistics at hand. |
|
|
| I'm not sure how (CPU) expensive statistic-gathering is, but if most of the= |
| work is reading the tuples, it might be a win to do this. |
| |
| Regards, |
| Mario Weilguni |
| |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 21 03:05:00 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 837AF475956 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 03:04:58 -0400 (EDT) |
| Received: from web80305.mail.yahoo.com (web80305.mail.yahoo.com |
| [66.218.79.21]) |
| by postgresql.org (Postfix) with SMTP id B71E4475461 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 03:04:57 -0400 (EDT) |
| Message-ID: <20021021070458.3513.qmail@web80305.mail.yahoo.com> |
| Received: from [203.87.150.116] by web80305.mail.yahoo.com via HTTP; |
| Mon, 21 Oct 2002 00:04:58 PDT |
| Date: Mon, 21 Oct 2002 00:04:58 -0700 (PDT) |
| From: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Subject: Default cost variables in postgresql.conf |
| To: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/105 |
| X-Sequence-Number: 122 |
| |
| Hi: |
| |
| Are the "cost" variables (e.g. |
| random_page_cost,cpu_tuple_cost,cpu_index_tuple_cost) |
| in postgresql.conf optimal for a particular set of |
| platform / hardware requirements? (i.e. the configs |
| works best for let say if you have PIII computer w/ |
| IDE as storage). |
| |
| I'm asking this since a lot of softwares' configs |
| are defaulted to a "conservative" settings where |
| allowances are given for people who have older/slower |
| CPUs(w/ not so large amount of memory). |
| |
| |
| Thank you in advance. |
| |
| ludwig. |
| |
| __________________________________________________ |
| Do you Yahoo!? |
| New DSL Internet Access from SBC & Yahoo! |
| http://sbc.yahoo.com |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 21 03:36:07 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id E20EF475FB9 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 03:36:04 -0400 (EDT) |
| Received: from bob.samurai.com (bob.samurai.com [205.207.28.75]) |
| by postgresql.org (Postfix) with ESMTP id 70A01476238 |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 03:35:38 -0400 (EDT) |
| Received: from tokyo.samurai.com (DU150.N224.ResNet.QueensU.CA |
| [130.15.224.150]) by bob.samurai.com (Postfix) with ESMTP |
| id DAE351D46; Mon, 21 Oct 2002 03:35:28 -0400 (EDT) |
| To: Mario Weilguni <mweilguni@sime.com> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: Self-generating statistics? |
| References: <200210210823.33744.mweilguni@sime.com> |
| From: Neil Conway <neilc@samurai.com> |
| In-Reply-To: <200210210823.33744.mweilguni@sime.com> |
| Date: 21 Oct 2002 03:34:56 -0400 |
| Message-ID: <87y98sz1lr.fsf@mailbox.samurai.com> |
| Lines: 27 |
| User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/106 |
| X-Sequence-Number: 123 |
| |
| Mario Weilguni <mweilguni@sime.com> writes: |
| > Many of the performance problems on pgsql-general seem to be related |
| > to the fact that no analyze is performed after the creation on the |
| > tables |
| |
| Well, there are lots of other ways an incompetent DBA can screw up a |
| database. The need to VACUUM and ANALYZE is stated clearly in the |
| docs. Providing workarounds for negligence isn't the right path to get |
| started down, IMHO. |
|
|
| That said, the general idea of a self-tuning database system has |
| merit, IMHO. For example, this paper proposes a histogram data |
| structure that can be updated fairly cheaply based on data gathered |
| from query execution: |
|
|
| http://citeseer.nj.nec.com/255752.html |
|
|
| A bunch of industry players (IBM, Microsoft, etc.) are putting some |
| work into this area (IBM calls it "autonomic computing", for |
| example). It might be an interesting area to look at in the future... |
|
|
| Cheers, |
|
|
| Neil |
|
|
| |
| Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Mon Oct 21 09:00:23 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id B2A4C475BEC |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 09:00:22 -0400 (EDT) |
| Received: from mail.libertyrms.com (unknown [209.167.124.227]) |
| by postgresql.org (Postfix) with ESMTP id A7A66475ADE |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 09:00:21 -0400 (EDT) |
| Received: from andrew by mail.libertyrms.com with local (Exim 3.22 |
| (Debian)) |
| id 183cAT-00049D-00 |
| for <pgsql-performance@postgresql.org>; Mon, 21 Oct 2002 09:00:25 -0400 |
| Date: Mon, 21 Oct 2002 09:00:25 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Self-generating statistics? |
| Message-ID: <20021021090025.B14840@mail.libertyrms.com> |
| Mail-Followup-To: pgsql-performance@postgresql.org |
| References: <200210210823.33744.mweilguni@sime.com> |
| Mime-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| Content-Disposition: inline |
| User-Agent: Mutt/1.2.5i |
| In-Reply-To: <200210210823.33744.mweilguni@sime.com>; |
| from mweilguni@sime.com on Mon, Oct 21, 2002 at 08:23:33AM +0200 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/107 |
| X-Sequence-Number: 124 |
|
|
| On Mon, Oct 21, 2002 at 08:23:33AM +0200, Mario Weilguni wrote: |
| > Something that might be worth considering: |
| > |
| > Many of the performance problems on pgsql-general seem to be |
| > related to the fact that no analyze is performed after the creation |
| > on the tables, so maybe this might be an option to fix that (in |
| > future releases): when a table has no statistics at all, and the |
| > first seq-scan on the table is |
|
|
| It's never the case that a table has no statistics at all. It has |
| default ones. Maybe they're right; it's hard to know. |
| |
| Someone has posted on gborg an anto-vacuum daemon that might be of |
| use in this situation. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 21 10:28:47 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id BC2E14766BC |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 10:17:37 -0400 (EDT) |
| Received: from mail.libertyrms.com (unknown [209.167.124.227]) |
| by postgresql.org (Postfix) with ESMTP id B2468476E4C |
| for <pgsql-performance@postgresql.org>; |
| Mon, 21 Oct 2002 10:16:16 -0400 (EDT) |
| Received: from andrew by mail.libertyrms.com with local (Exim 3.22 #3 |
| (Debian)) |
| id 183dLx-0005Go-00 |
| for <pgsql-performance@postgresql.org>; Mon, 21 Oct 2002 10:16:21 -0400 |
| Date: Mon, 21 Oct 2002 10:16:21 -0400 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| Subject: Re: Default cost variables in postgresql.conf |
| Message-ID: <20021021101621.A19970@mail.libertyrms.com> |
| Mail-Followup-To: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| References: <20021021070458.3513.qmail@web80305.mail.yahoo.com> |
| Mime-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| Content-Disposition: inline |
| User-Agent: Mutt/1.2.5i |
| In-Reply-To: <20021021070458.3513.qmail@web80305.mail.yahoo.com>; |
| from lud_nowhere_man@yahoo.com on Mon, Oct 21, 2002 at 12:04:58AM |
| -0700 |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/108 |
| X-Sequence-Number: 125 |
| |
| On Mon, Oct 21, 2002 at 12:04:58AM -0700, Ludwig Lim wrote: |
| > Hi: |
| > |
| > Are the "cost" variables (e.g. |
| > random_page_cost,cpu_tuple_cost,cpu_index_tuple_cost) |
| > in postgresql.conf optimal for a particular set of |
| > platform / hardware requirements? (i.e. the configs |
| |
| Not exactly. They're best guesses. If you check the admin guide, |
| you'll see that there's a note about these which says that there is |
| not a well-defined method for calculating these things, so you are |
| encouraged to experiment and share your findings. They _are_ known |
| to be conservative defaults, like everything else in the system. |
|
|
| A |
|
|
| |
| |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 22 07:47:36 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 46E4C475C26 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 22 Oct 2002 07:47:36 -0400 (EDT) |
| Received: from web80303.mail.yahoo.com (web80303.mail.yahoo.com |
| [66.218.79.19]) |
| by postgresql.org (Postfix) with SMTP id A6FB347592C |
| for <pgsql-performance@postgresql.org>; |
| Tue, 22 Oct 2002 07:47:35 -0400 (EDT) |
| Message-ID: <20021022114738.77366.qmail@web80303.mail.yahoo.com> |
| Received: from [203.87.150.116] by web80303.mail.yahoo.com via HTTP; |
| Tue, 22 Oct 2002 04:47:38 PDT |
| Date: Tue, 22 Oct 2002 04:47:38 -0700 (PDT) |
| From: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Subject: Selective usage of index in planner/optimizer (Too conservative?) |
| To: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/109 |
| X-Sequence-Number: 126 |
|
|
| Hi: |
|
|
| I was testing a database when notice that it does not |
| used the new index I created. So after a couple of |
| VACUUM ANALYZE it tried the following test queries. |
|
|
| **** TEST CASE |
| loyalty= |
| SET VARIABLE |
| loyalty= |
| where branch_cd=1 ; |
| NOTICE: QUERY PLAN: |
|
|
| Aggregate (cost=119123.54..119123.54 rows=1 width=0) |
| (actual time=811.08..811.0 |
| 8 rows=1 loops=1) |
| -> Index Scan using idx_monthly_branch on points |
| (cost=0.00..1187 |
| 65.86 rows=143073 width=0) (actual time=0.19..689.75 |
| rows=136790 loops=1) |
| Total runtime: 811.17 msec |
|
|
| ***** TEST CASE |
| loyalty= |
| SET VARIABLE |
| loyalty= |
| where branch_cd=1 ; |
| NOTICE: QUERY PLAN: |
|
|
| Aggregate (cost=62752.34..62752.34 rows=1 width=0) |
| (actual time=3593.93..3593.9 |
| 3 rows=1 loops=1) |
| -> Seq Scan on points (cost=0.00..62681.70 |
| rows=28254 width=0) (a |
| ctual time=0.33..3471.54 rows=136790 loops=1) |
| Total runtime: 3594.01 msec |
|
|
|
|
| *** TEST CASE |
| loyalty= |
| branch_cd=5; |
| NOTICE: QUERY PLAN: |
|
|
| Index Scan using idx_monthly_branch on points |
| (cost=0.00..49765.12 r |
| ows=16142 width=55) |
|
|
| |
|
|
| I am wondering why in test case |
| an index scan, where as in case |
| of rows in test |
| table "points". |
|
|
| The following are the number of elements in the |
| table: |
| branch_cd = 1 |
| branch_cd = 5 |
| count(*) |
|
|
| Its rather strange why "SELECT COUNT(*)...WHERE |
| branch_cd=1" uses sequential scan even though it just |
| comprises 5.3% of whole table... |
| |
| I'ts also strange because of the ff: (Remember test |
| case 1 and 2 are the same query) |
| |
| test 1 --> seq_scan=off --> 811.17 msec |
| test 2 --> seq_scan=on --> 3594.01 msec |
| |
| Test #1 have 400% improvement over Test #2, yet the |
| query plan for test #2 is the default. |
| |
| Are there way to let the planner improve the choice |
| in using an index or not? BTW the "cost" variables |
| are set to the default for the test. |
| |
| |
| Thank you in advance. |
| |
| ludwig. |
| |
| |
| __________________________________________________ |
| Do you Yahoo!? |
| New DSL Internet Access from SBC & Yahoo! |
| http://sbc.yahoo.com |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 22 10:24:22 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 7200547667E |
| for <pgsql-performance@postgresql.org>; |
| Tue, 22 Oct 2002 10:24:21 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id BBF11476678 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 22 Oct 2002 10:24:20 -0400 (EDT) |
| Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) |
| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g9MEOOhR018688; |
| Tue, 22 Oct 2002 10:24:25 -0400 (EDT) |
| To: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Cc: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| Subject: Re: Selective usage of index in planner/optimizer (Too conservative?) |
| In-reply-to: <20021022114738.77366.qmail@web80303.mail.yahoo.com> |
| References: <20021022114738.77366.qmail@web80303.mail.yahoo.com> |
| Comments: In-reply-to Ludwig Lim <lud_nowhere_man@yahoo.com> |
| message dated "Tue, 22 Oct 2002 04:47:38 -0700" |
| Date: Tue, 22 Oct 2002 10:24:24 -0400 |
| Message-ID: <18687.1035296664@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/110 |
| X-Sequence-Number: 127 |
| |
| Ludwig Lim <lud_nowhere_man@yahoo.com> writes: |
| > NOTICE: QUERY PLAN: |
| |
| > Aggregate (cost=119123.54..119123.54 rows=1 width=0) |
| > (actual time=811.08..811.0 |
| > 8 rows=1 loops=1) |
| > -> Index Scan using idx_monthly_branch on points |
| > (cost=0.00..1187 |
| > 65.86 rows=143073 width=0) (actual time=0.19..689.75 |
| > rows=136790 loops=1) |
| > Total runtime: 811.17 msec |
| |
| > NOTICE: QUERY PLAN: |
| |
| > Aggregate (cost=62752.34..62752.34 rows=1 width=0) |
| > (actual time=3593.93..3593.9 |
| > 3 rows=1 loops=1) |
| > -> Seq Scan on points (cost=0.00..62681.70 |
| > rows=28254 width=0) (a |
| > ctual time=0.33..3471.54 rows=136790 loops=1) |
| > Total runtime: 3594.01 msec |
| |
| Something fishy about this --- why is the estimated number of rows |
| different in the two cases (143073 vs 28254)? Did you redo VACUUM |
| and/or ANALYZE in between? |
| |
| > I am wondering why in test case #2 it did not use |
| > an index scan, where as in case #3 it did. |
| |
| Probably because it knows "branch_cd=5" is more selective than |
| "branch_cd=1". It would be useful to see the pg_stats entry for |
| branch_cd. |
| |
| > Its rather strange why "SELECT COUNT(*)...WHERE |
| > branch_cd=1" uses sequential scan even though it just |
| > comprises 5.3% of whole table... |
| |
| No, what's strange is that it's faster to use an indexscan for that. |
| The table must be very nearly in order by branch_cd; have you clustered |
| it recently? |
| |
| regards, tom lane |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 22 21:48:03 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 7F9F547610B |
| for <pgsql-performance@postgresql.org>; |
| Tue, 22 Oct 2002 21:48:01 -0400 (EDT) |
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| by postgresql.org (Postfix) with SMTP id B3FAF4760AA |
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| Tue, 22 Oct 2002 21:48:00 -0400 (EDT) |
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| Received: from [203.87.150.116] by web80310.mail.yahoo.com via HTTP; |
| Tue, 22 Oct 2002 18:48:04 PDT |
| Date: Tue, 22 Oct 2002 18:48:04 -0700 (PDT) |
| From: Ludwig Lim <lud_nowhere_man@yahoo.com> |
| Subject: Re: Selective usage of index in planner/optimizer (Too conservative?) |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Cc: PostgreSQL Mailing List <pgsql-performance@postgresql.org> |
| In-Reply-To: <18687.1035296664@sss.pgh.pa.us> |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=us-ascii |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/111 |
| X-Sequence-Number: 128 |
| |
| |
| --- Tom Lane <tgl@sss.pgh.pa.us> wrote: |
| > |
| > Something fishy about this --- why is the estimated |
| > number of rows |
| > different in the two cases (143073 vs 28254)? Did |
| > you redo VACUUM |
| > and/or ANALYZE in between? |
| |
| I neither VACUUMed nor ANALYZEd between the 2 |
| cases. |
| > |
| > > I am wondering why in test case #2 it did not |
| > use |
| > > an index scan, where as in case #3 it did. |
| > |
| > Probably because it knows "branch_cd=5" is more |
| > selective than |
| > "branch_cd=1". It would be useful to see the |
| > pg_stats entry for |
| > branch_cd. |
| |
| Should I try altering the statistics? I tried |
| ANALYZE points(branch_cd); |
| but it still gave me the same results. |
| |
| > > Its rather strange why "SELECT COUNT(*)...WHERE |
| > > branch_cd=1" uses sequential scan even though it |
| > just |
| > > comprises 5.3% of whole table... |
| |
| What I mean is the table is rather large. (2 |
| million rows) and I thought the planner would |
| automatically used an index to retrieve a small subset |
| (based on the percentage) of the large table. |
| |
| > No, what's strange is that it's faster to use an |
| > indexscan for that. |
| > The table must be very nearly in order by branch_cd; |
| > have you clustered |
| > it recently? |
| |
| I never clustered the table. |
| |
| But prior to testing I dropped an index and create |
| a new one. Does dropping and creating index "confuse" |
| the planner even after a VACUUM ANALYZE? |
| |
| I seem to notice this trend everytime I add a new |
| index to the table. It would slow down and the |
| performance would gradually improve in a day or two. |
| |
| Should I try changing "cost" variables? I'm using |
| Pentium IV, with SCSI [RAID 5]. |
|
|
| regards, |
|
|
| ludwig. |
|
|
|
|
| __________________________________________________ |
| Do you Yahoo!? |
| New DSL Internet Access from SBC & Yahoo! |
| http://sbc.yahoo.com |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 23 03:47:10 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 181DA475D70 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 03:47:07 -0400 (EDT) |
| Received: from serwer.skawsoft.com.pl (serwer.skawsoft.com.pl [213.25.37.66]) |
| by postgresql.org (Postfix) with ESMTP id B8EBA476020 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 03:47:05 -0400 (EDT) |
| Received: from klaster.net (pr150.krakow.cvx.ppp.tpnet.pl [213.76.42.150]) |
| by serwer.skawsoft.com.pl (Postfix) with ESMTP id D6BE62B2B9 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 09:40:33 +0200 (CEST) |
| Message-ID: <3DB65566.6060906@klaster.net> |
| Date: Wed, 23 Oct 2002 09:53:10 +0200 |
| From: Tomasz Myrta <jasiek@klaster.net> |
| User-Agent: Mozilla/5.0 (Windows; U; Win 9x 4.90; PL; rv:1.1) Gecko/20020826 |
| X-Accept-Language: pl, en-us, en |
| MIME-Version: 1.0 |
| To: pgsql-performance@postgresql.org |
| Subject: joining views |
| Content-Type: text/plain; charset=us-ascii; format=flowed |
| Content-Transfer-Encoding: 7bit |
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| X-Archive-Number: 200210/112 |
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|
|
| Hi |
| I'd like to split queries into views, but I can't join them - planner |
| search all of records instead of using index. It works very slow. |
|
|
| Here is example: |
| 1) create table1( |
| id1 integer primary key, |
| ...fields... |
| ); |
| table1 has thousands rows >40000. |
|
|
| 2) create index ind_pkey on table1(id1); |
|
|
| 3) create view some_view as select |
| id1,...fields... |
| from table1 |
| join ...(10 joins); |
|
|
| 4) create view another_view as select |
| id1,...fields... |
| from table1 |
| join ... (5 joins) |
| 4) Now here is the problem: |
| explain select * from some_view where id1=1234; |
| result: 100 |
|
|
| explain select * from another_view where id1=1234; |
| result: 80 |
|
|
| explain select * from some_view v1, another_view v2 |
| where v1.id1=1234 and v2.id1=1234 |
| result: 210 |
| Execution plan looks like planner finds 1 record from v1, so cost of |
| searching v1 is about 100. After this planner finds 1 record from v2 |
| (cost 80) and it's like I want to have. |
| |
| explain select * from some_view v1 join another_view v2 using(id1) |
| where v1.id1=1234; |
| result: 10000 (!) |
| |
| explain select * from some_view v1 join some_view v2 using(id1) |
| where v1.id1=1234; |
| result: 10000 (!) |
| Even joining the same view doesn't work well. |
|
|
| Execution plan looks like planner finds 1 record from v1, so cost of |
| searching v1 is about 100. After this planner search all of records from |
| v2 (40000 records, cost 9000) and then performs join with v1. |
|
|
| I know that I can make only single view without joining views, but it |
| makes me a big mess. |
|
|
| Regards, |
| Tomasz Myrta |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 23 10:31:21 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 07F8D476936 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 10:31:18 -0400 (EDT) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
| by postgresql.org (Postfix) with ESMTP id 0CDA647692F |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 10:31:17 -0400 (EDT) |
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| by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g9NEVJhR000983; |
| Wed, 23 Oct 2002 10:31:19 -0400 (EDT) |
| To: Tomasz Myrta <jasiek@klaster.net> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: joining views |
| In-reply-to: <3DB65566.6060906@klaster.net> |
| References: <3DB65566.6060906@klaster.net> |
| Comments: In-reply-to Tomasz Myrta <jasiek@klaster.net> |
| message dated "Wed, 23 Oct 2002 09:53:10 +0200" |
| Date: Wed, 23 Oct 2002 10:31:18 -0400 |
| Message-ID: <982.1035383478@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
| X-Virus-Scanned: by AMaViS new-20020517 |
| X-Archive-Number: 200210/113 |
| X-Sequence-Number: 130 |
|
|
| Tomasz Myrta <jasiek@klaster.net> writes: |
| > I'd like to split queries into views, but I can't join them - planner |
| > search all of records instead of using index. It works very slow. |
|
|
| I think this is the same issue that Stephan identified in his response |
| to your other posting ("sub-select with aggregate"). When you write |
| FROM x join y using (col) WHERE x.col = const |
| the WHERE-restriction is only applied to x. I'm afraid you'll need |
| to write |
| FROM x join y using (col) WHERE x.col = const AND y.col = const |
| Ideally you should be able to write just |
| FROM x join y using (col) WHERE col = const |
| but I think that will be taken the same as "x.col = const" :-( |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Wed Oct 23 10:56:27 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id AD85D476346 |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 10:56:26 -0400 (EDT) |
| Received: from serwer.skawsoft.com.pl (serwer.skawsoft.com.pl [213.25.37.66]) |
| by postgresql.org (Postfix) with ESMTP id 0287447623F |
| for <pgsql-performance@postgresql.org>; |
| Wed, 23 Oct 2002 10:56:26 -0400 (EDT) |
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| by serwer.skawsoft.com.pl (Postfix) with ESMTP |
| id 926F42B2B9; Wed, 23 Oct 2002 16:49:55 +0200 (CEST) |
| Message-ID: <3DB6BA0A.4060502@klaster.net> |
| Date: Wed, 23 Oct 2002 17:02:34 +0200 |
| From: Tomasz Myrta <jasiek@klaster.net> |
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| X-Accept-Language: pl, en-us, en |
| MIME-Version: 1.0 |
| To: Tom Lane <tgl@sss.pgh.pa.us> |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: joining views |
| References: <3DB65566.6060906@klaster.net> <982.1035383478@sss.pgh.pa.us> |
| Content-Type: text/plain; charset=ISO-8859-2; format=flowed |
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|
|
| U�ytkownik Tom Lane napisa�: |
|
|
| > I think this is the same issue that Stephan identified in his response |
| > to your other posting ("sub-select with aggregate"). When you write |
| > FROM x join y using (col) WHERE x.col = const |
| > the WHERE-restriction is only applied to x. I'm afraid you'll need |
| > to write |
| > FROM x join y using (col) WHERE x.col = const AND y.col = const |
| > Ideally you should be able to write just |
| > FROM x join y using (col) WHERE col = const |
| > but I think that will be taken the same as "x.col = const" :-( |
|
|
| I am sad, but you are right. Using views this way will look strange: |
|
|
| create view v3 as select |
| v1.id as id1, |
| v2.id as id2, |
| ... |
| from some_view v1, another_view v2; |
|
|
| select * from v3 where |
| id1=1234 and id2=1234; |
|
|
| Is it possible to make it look better? |
|
|
| And how to pass param=const to subquery ("sub-select with aggregate") if |
| I want to create view with this query? |
| Tomasz Myrta |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Sat Oct 26 06:27:52 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 25C494758BD |
| for <pgsql-performance@postgresql.org>; |
| Sat, 26 Oct 2002 06:27:49 -0400 (EDT) |
| Received: from technovell.com (213-97-10-232.uc.nombres.ttd.es |
| [213.97.10.232]) |
| by postgresql.org (Postfix) with ESMTP id C7295475843 |
| for <pgsql-performance@postgresql.org>; |
| Sat, 26 Oct 2002 06:27:47 -0400 (EDT) |
| Received: from pgsql [192.168.1.200] by technovell.com |
| with NIMS ModWeb Module; Sat, 26 Oct 2002 12:27:28 +0200 |
| Subject: Basic question about indexes/explain |
| From: Terry Yapt <pgsql@technovell.com> |
| To: pgsql-performance@postgresql.org |
| Date: Sat, 26 Oct 2002 12:27:28 +0200 |
| X-Mailer: NIMS ModWeb Module |
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|
|
| Hi all, |
|
|
| I have a basic doubt about indexes... in the next example: |
|
|
| |
| =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= |
| =3D=3D=3D |
| DROP TABLE ctest; |
| CREATE TABLE ctest |
| ( cusid numeric(5) PRIMARY KEY NOT NULL, |
| namec varchar(10) NOT NULL, |
| surnc varchar(20), |
| cashc numeric(10,4) |
| ); |
| CREATE INDEX ctest_cashc ON ctest (cashc); |
|
|
| INSERT INTO ctest VALUES (10,'Ten Custom','S.Ten Customer',1000); |
| INSERT INTO ctest VALUES (5 ,'Five Custo','S.Five Customer',500); |
| INSERT INTO ctest VALUES (8, 'Eigth Cust','S.Eigth Customer',800); |
| INSERT INTO ctest VALUES (90,'Nine Custo','S.Nine Customer',9000); |
| INSERT INTO ctest VALUES (70,'Seven Cust','S.Seven Customer',7000); |
|
|
| |
| explain SELECT * from ctest WHERE cusid between 5 AND 10 AND cashc < 1000; |
| explain SELECT * from ctest WHERE cusid =3D5 AND cashc =3D 1000; |
|
|
| CREATE INDEX ctest_othec ON ctest (cusid, cashc); |
|
|
| |
| explain SELECT * from ctest WHERE cusid between 5 AND 10 AND cashc < 1000; |
| explain SELECT * from ctest WHERE cusid =3D5 AND cashc =3D 1000; |
|
|
| |
| =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= |
| =3D=3D=3D |
|
|
| SELECTs executed before CREATE INDEX ctest_othec... are using index scan on= |
| PRIMARY KEY, but after the CREATE INDEX all SELECTs are using seq scan. |
|
|
| Seq Scan has lower cost than index scan (I think because there are few rows= |
| in table). |
|
|
| But if we have an index with the two colums I am using in the WHERE clause,= |
| why is the planner using seq scan ? (Or perhaps it is because too few row= |
| s in the table ?).... |
|
|
| Thanks.. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Sat Oct 26 07:40:10 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 1F9F1475843 |
| for <pgsql-performance@postgresql.org>; |
| Sat, 26 Oct 2002 07:40:09 -0400 (EDT) |
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| for <pgsql-performance@postgresql.org>; |
| Sat, 26 Oct 2002 07:40:06 -0400 (EDT) |
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| Sat, 26 Oct 2002 13:39:57 +0200 |
| Content-Type: text/plain; |
| charset="iso-8859-1" |
| From: Mario Weilguni <mweilguni@sime.com> |
| To: Terry Yapt <pgsql@technovell.com>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Basic question about indexes/explain |
| Date: Sat, 26 Oct 2002 13:40:06 +0200 |
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| X-Sequence-Number: 133 |
|
|
| Am Samstag, 26. Oktober 2002 12:27 schrieb Terry Yapt: |
| > Hi all, |
| > |
| snip |
| > I have a basic doubt about indexes... in the next example: |
| > But if we have an index with the two colums I am using in the WHERE claus= |
| e, |
| > why is the planner using seq scan ? (Or perhaps it is because too few ro= |
| ws |
| > in the table ?).... |
|
|
| First of all, you did not analyze your table (at least you did not mention = |
| you did). And an index is never a win for such a small table. I think the p= |
| lanner is fine here to select a seq scan, because your whole table is only = |
| 1 database page, so it would be no win to check the index here. |
|
|
| Everything is explained in the manual, check http://developer.postgresql.or= |
| g/docs/postgres/indexes.html |
|
|
| regards, |
| mario weilguni |
|
|
| From pgsql-performance-owner@postgresql.org Sat Oct 26 10:24:55 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Sat, 26 Oct 2002 10:24:55 -0400 (EDT) |
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| by postgresql.org (Postfix) with ESMTP id 67276475EB2 |
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| Sat, 26 Oct 2002 10:24:54 -0400 (EDT) |
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| Sat, 26 Oct 2002 10:24:53 -0400 (EDT) |
| To: Mario Weilguni <mweilguni@sime.com> |
| Cc: Terry Yapt <pgsql@technovell.com>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Basic question about indexes/explain |
| In-reply-to: <200210261340.06876.mweilguni@sime.com> |
| References: <1035628048.81bd0c0pgsql@technovell.com> |
| <200210261340.06876.mweilguni@sime.com> |
| Comments: In-reply-to Mario Weilguni <mweilguni@sime.com> |
| message dated "Sat, 26 Oct 2002 13:40:06 +0200" |
| Date: Sat, 26 Oct 2002 10:24:52 -0400 |
| Message-ID: <27301.1035642292@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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|
|
| Mario Weilguni <mweilguni@sime.com> writes: |
| > Everything is explained in the manual, check |
| > http://developer.postgresql.org/docs/postgres/indexes.html |
|
|
| In particular note the comments at the bottom of |
| http://developer.postgresql.org/docs/postgres/performance-tips.html: |
|
|
| "It is worth noting that EXPLAIN results should not be extrapolated to |
| situations other than the one you are actually testing; for example, |
| results on a toy-sized table can't be assumed to apply to large |
| tables. The planner's cost estimates are not linear and so it may well |
| choose a different plan for a larger or smaller table. An extreme |
| example is that on a table that only occupies one disk page, you'll |
| nearly always get a sequential scan plan whether indexes are available |
| or not. The planner realizes that it's going to take one disk page read |
| to process the table in any case, so there's no value in expending |
| additional page reads to look at an index." |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Sat Oct 26 18:35:27 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| pgsql-performance@postgresql.org; Sat, 26 Oct 2002 18:36:17 -0400 (EDT) |
| Date: Sat, 26 Oct 2002 18:36:05 -0400 |
| From: Carlos Moreno <moreno@mochima.com> |
| Subject: Setting shared buffers |
| To: pgsql-performance@postgresql.org |
| Message-id: <3DBB18D5.9070000@mochima.com> |
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|
|
|
|
| After checking some docs on performance tuning, I'm trying to |
| follow Bruce Momjian (sp??) advice to set the shared_buffers |
| at 25% of the amount of physical memory (1GB in our server) |
| and 4% for the sort_mem. |
| |
| When I try that, I get an error message when starting postgres, |
| complaining that the amount of shared memory requested exceeds |
| the maximum allowed by the kernel (they talk about increasing |
| the kernel parameter SHMMAX -- does this mean that I have to |
| recompile the kernel? Or is it just a "runtime" configuration |
| parameter that I set and on the next reboot will be taken?) |
| |
| To double check if I understood correctly: |
| |
| I have 1GB, so I want 256MB as shared buffers memory; each |
| shared buffer is 8kbytes, so I take 256M / 8k, which is 32k -- |
| so, I uncomment the line shared_buffers in the configuration |
| file, and put: |
| |
| shared_buffers = 32000 |
| |
| I don't touch anything else (max_connections keeps its default |
| value, but as I understand, that has nothing to do anyway... |
| right?) |
|
|
| So, what should I do? |
|
|
| Apologies if this is an FAQ |
| but I get a 404 - Not Found error when following the link to |
| the archives for this list :-( |
|
|
| Thanks in advance for any comments / advice ! |
|
|
| Carlos |
| |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Sat Oct 26 20:12:53 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Sat, 26 Oct 2002 20:12:51 -0400 (EDT) |
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| Sat, 26 Oct 2002 20:12:51 -0400 (EDT) |
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| with HTTP id 1800543; Sat, 26 Oct 2002 17:14:35 -0700 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Setting shared buffers |
| To: Carlos Moreno <moreno@mochima.com>, |
| pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Sat, 26 Oct 2002 17:14:35 -0700 |
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|
|
| Carlos, |
|
|
| > After checking some docs on performance tuning, I'm trying to |
| > follow Bruce Momjian (sp??) advice to set the shared_buffers |
| > at 25% of the amount of physical memory (1GB in our server) |
| > and 4% for the sort_mem. |
| |
| I tend to set my shared_buffers somewhat higher, but that's a good |
| place to start. Be cautious about sort_mem on a server with a lot of |
| users; sort_mem is not shared, so make sure that you have enough that |
| your server could handle 1-2 sorts per concurrent user without running |
| out of RAM. |
|
|
| > When I try that, I get an error message when starting postgres, |
| > complaining that the amount of shared memory requested exceeds |
| > the maximum allowed by the kernel (they talk about increasing |
| > the kernel parameter SHMMAX |
| > recompile the kernel? Or is it just a "runtime" configuration |
| > parameter that I set and on the next reboot will be taken?) |
|
|
| It's easy, on Linux don't even have to reboot. Other OS's are harder. |
| See this very helpful page: |
| http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/kernel-resources.html#SYSVIPC |
| |
| In fact, I tend to up my SHMMAX and SHMMALL and shared_buffers at night |
| on some databases, when they are doing automatic updates, and adjust |
| them back down during the day, when I want to prevent heavy user loads |
| from using up all system RAM. |
| |
| > I have 1GB, so I want 256MB as shared buffers memory; each |
| > shared buffer is 8kbytes, so I take 256M / 8k, which is 32k -- |
| > so, I uncomment the line shared_buffers in the configuration |
| > file, and put: |
| |
| See the calculations on the page link above. They are more specific |
| than that, and I have found the numbers there to be good estimates, |
| maybe only 10-20% high. |
| |
| -Josh Berkus |
| |
| From pgsql-general-owner@postgresql.org Mon Oct 28 08:25:37 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-general@postgresql.org>; |
| Mon, 28 Oct 2002 06:01:20 -0500 (EST) |
| Received: from news.hub.org (news.hub.org [64.49.215.80]) |
| by postgresql.org (Postfix) with ESMTP id 90BA74758E1 |
| for <pgsql-general@postgresql.org>; |
| Mon, 28 Oct 2002 06:01:20 -0500 (EST) |
| Received: by news.hub.org (Postfix, from userid 8) |
| id 32163381A35; Mon, 28 Oct 2002 06:01:18 -0500 (EST) |
| From: "Lars Maschke" <lars@gmeiner.de> |
| X-Newsgroups: comp.databases.postgresql.general, |
| comp.databases.postgresql.performance |
| Subject: [pgsql-performance] Performance Problems |
| Date: Mon, 28 Oct 2002 12:00:52 +0100 |
| Organization: Hub.Org Networking Services (http://www.hub.org) |
| Lines: 23 |
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| To: pgsql-performance@postgresql.org, pgsql-general@postgresql.org |
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| X-Archive-Number: 200210/1186 |
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| |
| Hello Newsgroup |
| |
| I have trouble with postgres 7.2.3. This system works fine, but last week |
| every postmaster process exhausted my system to 100%. What can i do ? When I |
| dump all databases it has 16MB. I start my system with the following |
| command: |
| |
| postmaster -i -c shared_buffers=1024 -c sort_mem=16384 -c |
| effective_cache_size=2048 -c max_connections=128 -c fsync=false -c |
| enable-seqscan=false -c enable_indexscan=false -c enable_tidscan=false -c |
| enable_sort=false -c enable_nestloop=false -c enable_hashjoin=false -c |
| enable-mergejoin=false -c show_parser_stats=false -c |
| show_planner_stats=false -c show_executor_stats=false -c |
| show_query_stats=false -c random_page_cost=0.99 -o -F |
| |
| Can someone help me ? |
| |
| -- |
| Lars Maschke |
| --- |
| Es gibt Tage, da verliert man und es gibt Tage, da gewinnen die anderen. |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 15:47:55 2002 |
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| Mon, 28 Oct 2002 12:47:52 PST |
| Date: Mon, 28 Oct 2002 12:47:52 -0800 (PST) |
| From: James Kelty <j_kelty@yahoo.com> |
| Subject: Clusters |
| To: pgsql-performance@postgresql.org |
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| |
| Hello, |
| |
| I have a question regarding clusters. What with all |
| the hoop-la about Oracle RAC, the question of |
| clustering PostgreSQL has come up at work. |
| |
| Now, I know that only one system can actually update |
| the database, and in a active/passive failover |
| situation that is ok. But! If I have lots and lots of |
| READS from the DB, can I cluster many low end systems |
| together behind an SLB? Assume that all systems have a |
| qlogic card, and are attached to a SAN, and that the |
| SAN holds the data. Can PostgreSQL be configured to |
| read from the SAN? Does each system have to initialize |
| the DB? |
| |
| I think this could greatly improve the perfomance from |
| a application appearance, but, so far I have only seen |
| documentation about Oracle RAC, DB2, and MySQL using |
| some sort of cluster software, be it, kimberlite, Red |
| Hat Cluster Manager, or Vertias Cluster Server. |
| |
| PostgreSQL seems to be our DB of choice, and I just |
| want to have a scalable solution via clustering for |
| it. No replication. Thanks for any thoughts! |
| |
| -James |
| |
| |
| ===== |
| James Kelty |
| 11742 NW Valley Vista Rd. |
| Hillsboro, OR 97124 |
| Cell: 541.621.5832 |
| j_kelty@yahoo.com |
| |
| __________________________________________________ |
| Do you Yahoo!? |
| Y! Web Hosting - Let the expert host your web site |
| http://webhosting.yahoo.com/ |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 15:59:27 2002 |
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| Date: Mon, 28 Oct 2002 15:59:27 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Clusters |
| Message-ID: <20021028155927.H21128@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
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| from j_kelty@yahoo.com on Mon, Oct 28, 2002 at 12:47:52PM -0800 |
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| |
| On Mon, Oct 28, 2002 at 12:47:52PM -0800, James Kelty wrote: |
| > together behind an SLB? Assume that all systems have a |
| > qlogic card, and are attached to a SAN, and that the |
| > SAN holds the data. Can PostgreSQL be configured to |
| > read from the SAN? Does each system have to initialize |
| > the DB? |
| |
| You can't do this safely. PostgreSQL wants to control its disk. |
| Someone has said on the (?) -general list that he has modified the |
| PostgreSQL code to do this, but it makes me nervous. |
|
|
| The Postgres-R project is trying to do something similar, but it's |
| some way from production quality. |
| |
| > it. No replication. Thanks for any thoughts! |
| |
| I sort of wonder why "no replication" is a requirement. If you want |
| lots of cheap, read-only machines, why not do it with replication? |
| You can buy a _lot_ of x86 boxes with Promise IDE RAID and big, fast |
| IDE drives for the price of ORAC. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 16:18:48 2002 |
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| Date: Mon, 28 Oct 2002 13:18:46 -0800 |
| From: Sean Chittenden <sean@chittenden.org> |
| To: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Clusters |
| Message-ID: <20021028211846.GM92719@perrin.int.nxad.com> |
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| |
| > > together behind an SLB? Assume that all systems have a qlogic |
| > > card, and are attached to a SAN, and that the SAN holds the |
| > > data. Can PostgreSQL be configured to read from the SAN? Does each |
| > > system have to initialize the DB? |
| > |
| > You can't do this safely. PostgreSQL wants to control its disk. |
| > Someone has said on the (?) -general list that he has modified the |
| > PostgreSQL code to do this, but it makes me nervous. |
|
|
| Didn't Tom say that it was possible if you had different WAL logs for |
| each instance? ie, just share the data directory, but everything else |
| has to be on a per instance basis. Check the archives, someone just |
| asked about this a week ago or so. -sc |
| |
| -- |
| Sean Chittenden |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 16:32:15 2002 |
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| Date: Mon, 28 Oct 2002 16:32:16 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Clusters |
| Message-ID: <20021028163216.I21128@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
| References: <20021028204752.45338.qmail@web13901.mail.yahoo.com> |
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| from sean@chittenden.org on Mon, Oct 28, 2002 at 01:18:46PM -0800 |
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| |
| On Mon, Oct 28, 2002 at 01:18:46PM -0800, Sean Chittenden wrote: |
| > |
| > Didn't Tom say that it was possible if you had different WAL logs for |
| > each instance? ie, just share the data directory, but everything else |
| > has to be on a per instance basis. Check the archives, someone just |
| > asked about this a week ago or so. -sc |
|
|
| As Sean says, check the archives. But I think the problem is bigger |
| than just the WAL. For instance, the pidfile is in the data |
| directory, so each system is going to try to overwrite that. Plus, |
| there's no read-only mode for Postgres, so if one of the systems |
| writes where it shouldn't, you'll blow everything away. I can |
| appreciate that some people like to play at the bare metal this way, |
| but it gives me ulcers ;-) |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 16:56:19 2002 |
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| Date: Mon, 28 Oct 2002 13:56:14 -0800 |
| To: pgsql-performance@postgresql.org |
| From: eric soroos <eric-psql@soroos.net> |
| Subject: Low Budget Performance |
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| |
| I'm looking for some advice or benchmarks comparing low end systems for a postgres installation. |
|
|
| Currently, I've got postgres running on the same system as the app server accessing a single fast IDE drive. The database is on the order of 1 gig, with two main tables accounting for 98% of the data. Between the app servers and the database, I'm pretty sure that neither of the main tables are cached in memory for any significant time. I'm guessing that this is sub optimal. (The data size is 1 gig now, but I will be adding more 1 gig databases to this system in the near future) I'm planning to split this into an app server and database server. |
|
|
| In an ideal world, I'd throw a lot of 15k scsi/raid0+1 at this. But I don't have an ideal world budget. I've got more of an ide world budget, if that. (~1k) |
| |
| I know the first order of business is to ignore the hardware and make sure that I've got all of the table scans found and turned into indexes. I'm still working on that. Are there any tools that save queries and the plans, then report on the ones that are the biggest performance drags? |
| |
| But since I do software, it's obviously a hardware problem. ;> |
|
|
| My hardware options: |
|
|
| Processor: |
|
|
| * My low cost option is to repurpose an under used p3 with onboard IDE raid and pc133 memory. The high cost option is to get a new mid range Athalon with 266/ddr memory. Will maxing out the memory mean that whatever I don't use for client connections will be used for caching the drive system? (most likely, I will be running debian woody with a 2.4 series kernel) |
| |
| Drives: |
| |
| * The cost difference between IDE and SCSI is roughly a factor of 2-4x. (100 gig 7200 rpm IDE can be had for a little over $100, 10k 36 gig SCSI is about $200. Am I better off throwing twice as many (4) IDE disks at the system? Does it change if I can put each IDE drive on its own channel? |
| |
| Drive Layout: |
| |
| * What Drive layout? |
| |
| Raid? |
| 0 gives better latency if the controller reads from whichever gets the data first. It's unclear if IDE or software raid actually does this though. |
| 1 Gives better throughput, at a cost to latency. |
| 5 Like 1 but with redundancy. It's unclear if I'll be able to do this without hardware SCSI raid. |
|
|
| Non Raid? |
| I've read about seperating table spaces on different drives, so that indexes and data can be written at the same time. This advice appears to be tailored to the complexity of oracle. The ideal configuration according to this info appears to be multiple drives, all mirrored individually. |
| |
| Does the write ahead logging of PG mean that no matter what indexes and data are changed, that there will be one sync to disk? Does this reduce the penalty of indexes? WAL seems to mean that to get performance out of a drive array, I'd want to use the fastest (latency/throughput) logical single image I could get, not a collection of mirrored drives. |
|
|
| I'd appreciate any insight. |
| |
| eric |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 17:07:13 2002 |
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| Mon, 28 Oct 2002 17:07:11 -0500 (EST) |
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| pgsql-performance@postgresql.org; Mon, 28 Oct 2002 17:07:17 -0500 (EST) |
| Date: Mon, 28 Oct 2002 17:07:42 -0500 |
| From: Carlos Moreno <moreno@mochima.com> |
| Subject: Re: Setting shared buffers |
| To: pgsql-performance@postgresql.org |
| Message-id: <3DBDB52E.500@mochima.com> |
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| |
| |
| Thanks John! This is very helpful... |
| |
| Just one detail I'd like to double check: |
| |
|
|
| >It's easy, on Linux don't even have to reboot. Other OS's are harder. |
| > See this very helpful page: |
| >http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/kernel-resources.html#SYSVIPC |
| > |
| >In fact, I tend to up my SHMMAX and SHMMALL and shared_buffers [...] |
| > |
| |
| According to that document, I should put the same value for the |
| SHMMAX and SHMMALL -- however, when I do: |
| |
| cat /proc/sys/kernel/shmmax |
| cat /proc/sys/kernel/shmmall |
| |
| on my Linux system (RedHat 7.3, soon to upgrade to 8.0), I |
| get different values, shmmall being shmmax divided by 16 |
| |
| Is that normal? What should I do? Should I follow the exact |
| same instructions from that document and set both to the |
| exact same value? |
| |
| Are the default values set that way (i.e., different values) |
| for some strange reason, or is it that on the 2.4 kernel |
| the shmmall is indicated in blocks of 16 bytes or something |
| like that? |
| |
| Thanks! |
| |
| Carlos |
| -- |
| |
| |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 19:00:38 2002 |
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| Mon, 28 Oct 2002 16:00:38 PST |
| Date: Mon, 28 Oct 2002 16:00:38 -0800 (PST) |
| From: James Kelty <j_kelty@yahoo.com> |
| Subject: Re: Clusters |
| To: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| In-Reply-To: <20021028155927.H21128@mail.libertyrms.com> |
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| |
| I've just been very unhappy with the ease of use for |
| Postgres replication. Pgreplicator was a huge pain |
| that worked less often than not, rserv was really |
| unmanageable. I haven't had a chance to look at |
| dbmirror yet, though. Plus the replication would start |
| to chew up network bandwidth at some point. Of course, |
| so would reading from the SAN. But, then there is the |
| issue of system failure. If the system has to be |
| re-imaged, then I'd have to take a snap shot of the |
| master, and re-apply it to the new system. It just |
| seems more manageable if I can plug in a new Postgres |
| 'instance' to the SAN, and have it up to date the |
| minute it starts. I know that postgres doesn't have a |
| 'read-only' mode, but it does have the GRANT option. |
| So, access to the DB _can_ be controlled that way at |
| least. |
| |
| Anyway, thanks for all the thoughts and info. If |
| anyone knows of some other replication service besides |
| the two listed above, great! Let me know! |
| |
| Lemme just say, that the feature set of Postgres, when |
| talking strictly database, is AWESOME. Really easy to |
| work with, and around, but, in the HA world, it seems |
| a little difficult to work with. |
| |
| Thanks again, Guys! |
| |
| -James |
| |
| --- Andrew Sullivan <andrew@libertyrms.info> wrote: |
| > On Mon, Oct 28, 2002 at 12:47:52PM -0800, James |
| > Kelty wrote: |
| > > together behind an SLB? Assume that all systems |
| > have a |
| > > qlogic card, and are attached to a SAN, and that |
| > the |
| > > SAN holds the data. Can PostgreSQL be configured |
| > to |
| > > read from the SAN? Does each system have to |
| > initialize |
| > > the DB? |
| > |
| > You can't do this safely. PostgreSQL wants to |
| > control its disk. |
| > Someone has said on the (?) -general list that he |
| > has modified the |
| > PostgreSQL code to do this, but it makes me nervous. |
| > |
| > The Postgres-R project is trying to do something |
| > similar, but it's |
| > some way from production quality. |
| > |
| > > it. No replication. Thanks for any thoughts! |
| > |
| > I sort of wonder why "no replication" is a |
| > requirement. If you want |
| > lots of cheap, read-only machines, why not do it |
| > with replication? |
| > You can buy a _lot_ of x86 boxes with Promise IDE |
| > RAID and big, fast |
| > IDE drives for the price of ORAC. |
| > |
| > A |
| > |
| > -- |
| > ---- |
| > Andrew Sullivan 204-4141 |
| > Yonge Street |
| > Liberty RMS Toronto, |
| > Ontario Canada |
| > <andrew@libertyrms.info> |
| > M2P 2A8 |
| > +1 416 646 |
| > 3304 x110 |
| > |
| > |
| > ---------------------------(end of |
| > broadcast)--------------------------- |
| > TIP 6: Have you searched our list archives? |
| > |
| > http://archives.postgresql.org |
| |
| |
| ===== |
| James Kelty |
| 11742 NW Valley Vista Rd. |
| Hillsboro, OR 97124 |
| Cell: 541.621.5832 |
| j_kelty@yahoo.com |
| |
| __________________________________________________ |
| Do you Yahoo!? |
| Y! Web Hosting - Let the expert host your web site |
| http://webhosting.yahoo.com/ |
| |
| From pgsql-performance-owner@postgresql.org Mon Oct 28 22:27:33 2002 |
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| for <pgsql-performance@postgresql.org>; Mon, 28 Oct 2002 22:27:36 -0500 |
| Date: Mon, 28 Oct 2002 22:27:36 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Clusters |
| Message-ID: <20021028222736.A18141@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
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| from j_kelty@yahoo.com on Mon, Oct 28, 2002 at 04:00:38PM -0800 |
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| |
| On Mon, Oct 28, 2002 at 04:00:38PM -0800, James Kelty wrote: |
| |
| > that worked less often than not, rserv was really |
| > unmanageable. |
| |
| We use PostgreSQL, Inc's eRserver, which is a commercial version of |
| the code in contrib/, and I can say that it is not unmanageable, but |
| it is some work at first. The commercial version is an improvement |
| on the contrib/ code, though. For us, it's worth it; but you have to |
| decide that for yourself. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 29 01:30:20 2002 |
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| From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> |
| To: pgsql-performance@postgresql.org |
| Date: Tue, 29 Oct 2002 12:00:45 +0530 |
| MIME-Version: 1.0 |
| Subject: Re: Low Budget Performance |
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| |
| On 28 Oct 2002 at 13:56, eric soroos wrote: |
| |
| > Currently, I've got postgres running on the same system as the app server accessing a single fast IDE drive. The database is on the order of 1 gig, with two main tables accounting for 98% of the data. Between the app servers and the database, I'm pretty sure that neither of the main tables are |
| cached in memory for any significant time. I'm guessing that this is sub optimal. (The data size is 1 gig now, but I will be adding more 1 gig databases to this system in the near future) I'm planning to split this into an app server and database server. |
| > |
| > In an ideal world, I'd throw a lot of 15k scsi/raid0+1 at this. But I don't have an ideal world budget. I've got more of an ide world budget, if that. (~1k) |
| > |
| > I know the first order of business is to ignore the hardware and make sure that I've got all of the table scans found and turned into indexes. I'm still working on that. Are there any tools that save queries and the plans, then report on the ones that are the biggest performance drags? |
| > |
| > But since I do software, it's obviously a hardware problem. ;> |
| > |
| > My hardware options: |
| |
| I would say throw a lot of RAM no matter what type. Even PC133 is going to be |
| faster than any disk you can buy anytimes. I would say 2Gig is a nice place to |
| start. |
| |
| A gig is not much of a database but a lot depends upon what do you do with the |
| data. Obviously 50 clients doing sequential scan with rows ordered in random |
| fashion would chew any box,..;-) |
| |
| Processor does not matter much. But I would advice to split app server and |
| database server ASAP. |
| |
| Well, IDE RAID looks like nice optio to me, but before finalising RAID config., |
| I would advice to test performance and scalability with separate database |
| server and couple of Gigs of RAM. Because if this configuration is sufficient |
| for your need, probably you can choose a conservatice RAID config that would |
| enhance availability rather than getting every ounce of performance out of it. |
| As far as possible, don't compramise with storage availability. |
|
|
| > Does the write ahead logging of PG mean that no matter what indexes and data are changed, that there will be one sync to disk? Does this reduce the penalty of indexes? WAL seems to mean that to get performance out of a drive array, I'd want to use the fastest (latency/throughput) logical |
| single image I could get, not a collection of mirrored drives. |
| |
| I guess RAID will take care of lot of these issues. Besides if you use volume |
| manager you can add partitions from different disks, effectively splitting the |
| IO. Of course, you can shutdown the database and symlink things to another |
| drive, but that's hack and nothing else. Don't do it as far as possible.. |
| |
| HTH |
| |
| Bye |
| Shridhar |
| |
| -- |
| You're dead, Jim. |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 01:41:36 2002 |
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| Tue, 29 Oct 2002 01:41:34 -0500 (EST) |
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| charset="iso-8859-1" |
| From: Mario Weilguni <mweilguni@sime.com> |
| To: eric soroos <eric-psql@soroos.net>, |
| pgsql-performance@postgresql.org |
| Subject: Re: Low Budget Performance |
| Date: Tue, 29 Oct 2002 08:07:50 +0100 |
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|
|
| Am Montag, 28. Oktober 2002 22:56 schrieb eric soroos: |
| > Raid? |
| > 0 gives better latency if the controller reads from whichever gets the da= |
| ta |
| > first. It's unclear if IDE or software raid actually does this though. 1 |
| > Gives better throughput, at a cost to latency. |
| > 5 Like 1 but with redundancy. It's unclear if I'll be able to do this |
| > without hardware SCSI raid. |
| |
| Just for the raid part, we've very good expiriences with Raid 10. Performs = |
| well and has mirroring. Avoid Raid 5 if possible, write performance will su= |
| ffer greatly. |
|
|
| Regards, |
| Mario Weilguni |
|
|
| From pgsql-general-owner@postgresql.org Tue Oct 29 08:38:23 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| id 03BFA4765BA; Tue, 29 Oct 2002 08:38:22 -0500 (EST) |
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| by postgresql.org (Postfix) with ESMTP |
| id B08374765B0; Tue, 29 Oct 2002 08:38:20 -0500 (EST) |
| Received: from andrew by mail.libertyrms.com with local (Exim 3.22 |
| (Debian)) |
| id 186WZc-000590-00; Tue, 29 Oct 2002 08:38:24 -0500 |
| Date: Tue, 29 Oct 2002 08:38:24 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org, pgsql-general@postgresql.org |
| Subject: Re: [pgsql-performance] Performance Problems |
| Message-ID: <20021029083824.C18292@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org, pgsql-general@postgresql.org |
| References: <90iv8-n4s.ln1@server.csg.de> |
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| from lars@gmeiner.de on Mon, Oct 28, 2002 at 12:00:52PM +0100 |
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|
|
| On Mon, Oct 28, 2002 at 12:00:52PM +0100, Lars Maschke wrote: |
| > Can someone help me ? |
|
|
| Maybe. You need to tell us what "exhausted your system" means. Did |
| it crash? Were you swapping? Were your CPUs pegged? |
|
|
| A |
|
|
|
|
| |
| |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 08:43:41 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 90AED476032 |
| for <pgsql-performance@postgresql.org>; |
| Tue, 29 Oct 2002 08:43:40 -0500 (EST) |
| Received: from sss.pgh.pa.us (unknown [192.204.191.242]) |
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| Tue, 29 Oct 2002 08:43:38 -0500 (EST) |
| To: Sean Chittenden <sean@chittenden.org> |
| Cc: Andrew Sullivan <andrew@libertyrms.info>, pgsql-performance@postgresql.org |
| Subject: Re: Clusters |
| In-reply-to: <20021028211846.GM92719@perrin.int.nxad.com> |
| References: <20021028204752.45338.qmail@web13901.mail.yahoo.com> |
| <20021028155927.H21128@mail.libertyrms.com> |
| <20021028211846.GM92719@perrin.int.nxad.com> |
| Comments: In-reply-to Sean Chittenden <sean@chittenden.org> |
| message dated "Mon, 28 Oct 2002 13:18:46 -0800" |
| Date: Tue, 29 Oct 2002 08:43:38 -0500 |
| Message-ID: <21026.1035899018@sss.pgh.pa.us> |
| From: Tom Lane <tgl@sss.pgh.pa.us> |
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| X-Archive-Number: 200210/131 |
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|
|
| Sean Chittenden <sean@chittenden.org> writes: |
| > together behind an SLB? Assume that all systems have a qlogic |
| > card, and are attached to a SAN, and that the SAN holds the |
| > data. Can PostgreSQL be configured to read from the SAN? Does each |
| > system have to initialize the DB? |
| >> |
| >> You can't do this safely. PostgreSQL wants to control its disk. |
| >> Someone has said on the (?) -general list that he has modified the |
| >> PostgreSQL code to do this, but it makes me nervous. |
| |
| > Didn't Tom say that it was possible if you had different WAL logs for |
| > each instance? |
|
|
| I said no such thing. I said it will not work, period. |
|
|
| regards, tom lane |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 09:26:36 2002 |
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| Tue, 29 Oct 2002 08:26:37 -0600 (CST) |
| Date: Tue, 29 Oct 2002 08:26:37 -0600 |
| From: Kenny H Klatt <kklatt@alpha3.csd.uwm.edu> |
| To: pgsql-performance@postgresql.org |
| Subject: Possible OT - Benchmark test for 7.3 Beta 3 |
| Message-ID: <20021029142637.GA11684@alpha3.csd.uwm.edu> |
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|
| Hi: |
| Not being too versed with postgres and beta tests, is there |
| a place or person who would review the results of the benchmark test for 7.3? |
|
|
| kklatt@uwm.edu |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 10:15:54 2002 |
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| for <pgsql-performance@postgresql.org>; Tue, 29 Oct 2002 10:15:56 -0500 |
| Date: Tue, 29 Oct 2002 10:15:56 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Possible OT - Benchmark test for 7.3 Beta 3 |
| Message-ID: <20021029101556.B25851@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
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| from kklatt@alpha3.csd.uwm.edu on Tue, Oct 29, 2002 at 08:26:37AM |
| -0600 |
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|
|
| On Tue, Oct 29, 2002 at 08:26:37AM -0600, Kenny H Klatt wrote: |
| > Hi: |
| > Not being too versed with postgres and beta tests, is there |
| > a place or person who would review the results of the benchmark test for 7.3? |
|
|
| I'm unaware of anyone having done a benchmark. If you know of one, |
| please share it with all of us. |
| |
| A |
| |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 29 11:58:42 2002 |
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| Tue, 29 Oct 2002 11:58:39 -0500 (EST) |
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| Tue, 29 Oct 2002 09:00:27 -0800 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Low Budget Performance |
| To: pgsql-performance@postgresql.org |
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| Date: Tue, 29 Oct 2002 09:00:27 -0800 |
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| |
| Eric, |
| |
| > > Currently, I've got postgres running on the same system as the app |
| > server accessing a single fast IDE drive. The database is on the |
| > order of 1 gig, with two main tables accounting for 98% of the data. |
| > Between the app servers and the database, I'm pretty sure that |
| > neither of the main tables are |
| > cached in memory for any significant time. I'm guessing that this is |
| > sub optimal. (The data size is 1 gig now, but I will be adding more 1 |
| > gig databases to this system in the near future) I'm planning to |
| > split this into an app server and database server. |
| |
| One gig is a large database for a single IDE drive -- especially with |
| multiple client connections. |
| |
| > > In an ideal world, I'd throw a lot of 15k scsi/raid0+1 at this. |
| > But I don't have an ideal world budget. I've got more of an ide |
| > world budget, if that. (~1k) |
|
|
| Well, no matter how many performance tricks you add in, the speed will |
| be limited by the hardware. Make sure that your client/employer knows |
| that *before* they complain about the speed. |
|
|
| > > I know the first order of business is to ignore the hardware and |
| > make sure that I've got all of the table scans found and turned into |
| > indexes. I'm still working on that. Are there any tools that save |
| > queries and the plans, then report on the ones that are the biggest |
| > performance drags? |
|
|
| Not exactly. If you enable Postgres 7.2 STATISTICS, you can get a lot |
| of information about which indexes are being used, which are not, and |
| which tables are having a lot of table scans. A tool like you |
| describe would be really, really useful |
| one, I'm sure you could sell it for $$$$. |
| |
| > > But since I do software, it's obviously a hardware problem. ;> |
|
|
| <grin> |
|
|
| Actually, your best option for the hardware is to test what portion of |
| the hardware is bottlenecking your performance, and address that. But |
| first: |
|
|
| > Well, IDE RAID looks like nice optio to me, but before finalising |
| > RAID config., |
| > I would advice to test performance and scalability with separate |
| > database |
| > server and couple of Gigs of RAM. |
|
|
| I'm not convinced that current IDE RAID actually improves database disk |
| throughput -- there's a lot of overhead in the one controller I tried |
| (Promise). Does anyone have some statistics they can throw at me? |
|
|
| A cheaper and easier method, involving 3-4 disks: |
|
|
| Channel 1, Disk 1: Operating System, Swap, and PostgreSQL log |
| Channel 1, Disk 2: WAL Files |
| Channel 2, Disk 1: Database |
| Channel 2, Disk 2 (optional): 2nd database data |
|
|
| *however*, if you have multiple databases being simulteaneously |
| accessesed, you will want to experiment with shuffling around the |
| databases and WAL files to put them on different disks. The principle |
| is to divide the disk tasks that are simultaenous ammonng as many disks |
| as possible; thus the WAL files always do better on a different disk |
| and channel than the database. |
|
|
| > > Does the write ahead logging of PG mean that no matter what indexes |
| > and data are changed, that there will be one sync to disk? Does this |
| > reduce the penalty of indexes? |
|
|
| In a word: No. Depending on the size of the update, there may be |
| multiple synchs. And indexes do carry a significant penalty on large |
| updates; just try runninng 10,000 updates to an indexed column as one |
| transaction, and the penalty will be obvious. In fact, for my data |
| load procedures, I tend to drop and re-create indexes. |
|
|
| > WAL seems to mean that to get |
| > performance out of a drive array, I'd want to use the fastest |
| > (latency/throughput) logical |
| > single image I could get, not a collection of mirrored drives. |
| |
| Mirrored drives are different than RAID. However, you are correct |
| that the redundancy/fail-over factor in some RAID and Mirroring comes |
| at a performance penalty. |
| |
| But you need to determine where you are actually losing time. |
| Assuming that your tables are correctly indexed, your files are |
| distributed, and your database is VACUUM FULL ANALYZed, and your |
| postgresql.conf configured for optimum use of your exisiting memory, |
| then here's what you do (assuming that you use Linux) |
|
|
| 1. From a workstation, open 2 terminal windows on the server. In #1, |
| run "vmstat 3", in the other "top" |
|
|
| 2. Have your users pound on the application, trying all of the most |
| complicated (and slow) operations in the app. More users is better, |
| for this test. |
|
|
| 3. Watch Vmstat and Top. What you're looking for is: |
| |
| a) Is the processor at 75% or above? If so, you either need a faster |
| processor or more efficient queries |
| |
| b) Is the system using 80-100% of the RAM which you allocated it? If |
| so, add more RAM and increase the Postgresql.conf memory variables. |
| |
| c) Is the system using Swap memory? if so, either add more RAM, or |
| *decrease* the postgresql.conf memory variables. |
| |
| d) Are RAM and Processor at less than 50%, but the Disk I/O reaches a |
| maximum number and stays there for minutes? Then your disk channel is |
| flooded, and you cannot improve performance except by either improving |
| your queries so the pull less rows, or adding more/faster disk |
| capacity. |
| |
| The above process, while drawn-out, will help you avoid spending a lot |
| of money on, for example, RAM that won't make a difference. |
|
|
| -Josh Berkus |
|
|
|
|
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 12:08:31 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
| by postgresql.org (Postfix) with ESMTP id 3AA5F475DBC |
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| Tue, 29 Oct 2002 12:08:29 -0500 (EST) |
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| with HTTP id 1803616; Tue, 29 Oct 2002 09:10:31 -0800 |
| From: "Josh Berkus" <josh@agliodbs.com> |
| Subject: Re: Low Budget Performance |
| To: Mario Weilguni <mweilguni@sime.com>, |
| eric soroos <eric-psql@soroos.net>, pgsql-performance@postgresql.org |
| X-Mailer: CommuniGate Pro Web Mailer v.3.5.9 |
| Date: Tue, 29 Oct 2002 09:10:31 -0800 |
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|
|
| Mario, |
| |
| > Just for the raid part, we've very good expiriences with Raid 10. |
| > Performs well and has mirroring. Avoid Raid 5 if possible, write |
| > performance will suffer greatly. |
| |
| Out of curiousity, what is it with RAID 5? I've encountered the poor |
| write performance too ... any idea why? |
|
|
| -Josh |
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 12:31:07 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| Tue, 29 Oct 2002 12:31:05 -0500 (EST) |
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| for <pgsql-performance@postgresql.org>; Tue, 29 Oct 2002 12:31:10 -0500 |
| Date: Tue, 29 Oct 2002 12:31:10 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Low Budget Performance |
| Message-ID: <20021029123110.M25851@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
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| from josh@agliodbs.com on Tue, Oct 29, 2002 at 09:10:31AM -0800 |
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|
|
| On Tue, Oct 29, 2002 at 09:10:31AM -0800, Josh Berkus wrote: |
| > |
| > Out of curiousity, what is it with RAID 5? I've encountered the poor |
| > write performance too ... any idea why? |
| |
| It largely depends on the controller and te implementation. It has |
| to do with the cost of calculating the checksum. If the |
| implementation of that is inefficient, the writes become inefficient. |
| |
| A |
| |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 29 13:43:41 2002 |
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| Date: Tue, 29 Oct 2002 10:43:33 -0800 |
| To: pgsql-performance@postgresql.org |
| From: eric soroos <eric-psql@soroos.net> |
| Subject: Re: Low Budget Performance |
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| |
| Josh, |
| |
| Thanks for the reply. |
| |
| > One gig is a large database for a single IDE drive -- especially with |
| > multiple client connections. |
| |
| That's good to know. |
|
|
| Is a scsi system that much better? Looking at prices, scsi is 1/2 the capacity and double the price for the 80 gig 7200rpm ide vs 36 gig 10k rpm scsi. Assuming that I'll never run out of space before running out of performance, I can dedicate 2x the number of ide drives to the problem. |
| |
| > > Well, IDE RAID looks like nice optio to me, but before finalising |
| > > RAID config., |
| > > I would advice to test performance and scalability with separate |
| > > database |
| > > server and couple of Gigs of RAM. |
| > |
| > I'm not convinced that current IDE RAID actually improves database disk |
| > throughput |
| > (Promise). Does anyone have some statistics they can throw at me? |
|
|
| All of the benchmarks that I've seen show that IDE raid is good for large operations, but for random seek and small data transfers, you don't get anywhere near the expected scaling. |
|
|
| > A cheaper and easier method, involving 3-4 disks: |
| > |
| > Channel 1, Disk 1: Operating System, Swap, and PostgreSQL log |
| > Channel 1, Disk 2: WAL Files |
| > Channel 2, Disk 1: Database |
| > Channel 2, Disk 2 (optional): 2nd database data |
|
|
| With IDE, I think I can manage to put each drive on a seperate channel. I've either got one extra controller onboard, or I can add a 4 channel pci card. From what I've read, this is one of the more important factors in IDE performance. |
|
|
| > *however*, if you have multiple databases being simulteaneously |
| > accessesed, you will want to experiment with shuffling around the |
| > databases and WAL files to put them on different disks. The principle |
| > is to divide the disk tasks that are simultaenous ammonng as many disks |
| > as possible; thus the WAL files always do better on a different disk |
| > and channel than the database. |
|
|
| That's what I've read about database disk system design. Reduce spindle contention by using lots of drives. (especially in Philip Greenspun's book, but he's talking about 2x7 drives as a minimal configuration and 2x21 as ideal for larger systems. And when licensing is more expensive than that sort of drive system, it's all roundoff error.) |
| |
| So, assuming that I have three databases with roughly equal load on them, does it make sense to partition them like: |
| |
| disk 0: os/swap/log/backup staging |
| disk 1: WAL 1, DB 2 |
| disk 2: WAL 2, DB 3 |
| disk 3: WAL 3, DB 1 |
| |
| Or, in a slightly bigger drive system split 2 ways then mirrored. |
| disk 0: os etc |
| Disk 1,2: WAL 1, DB 2 |
| Disk 3,4: WAL 2, DB 1 |
| |
| From an admin point of view, would this be done with alternate locations, symlinks, or multiple concurrent pg processes? |
| |
| > > > Does the write ahead logging of PG mean that no matter what indexes |
| > > and data are changed, that there will be one sync to disk? Does this |
| > > reduce the penalty of indexes? |
| > |
| > In a word: No. Depending on the size of the update, there may be |
| > multiple synchs. And indexes do carry a significant penalty on large |
| > updates; just try runninng 10,000 updates to an indexed column as one |
| > transaction, and the penalty will be obvious. In fact, for my data |
| > load procedures, I tend to drop and re-create indexes. |
| |
| Most of my update procedures are single row updates, with the exception being things that are already background tasks that the user doesn't notice the difference between 10 and 20 sec. So maybe I'm lucky there. |
| |
| > Mirrored drives are different than RAID. However, you are correct |
| > that the redundancy/fail-over factor in some RAID and Mirroring comes |
| > at a performance penalty. |
| |
| From howtos I've seen, there _can_ be a speed boost with mirroring on read using the linux kernel raid 1. Write performance suffers though. |
| |
| > But you need to determine where you are actually losing time. |
|
|
| That looks like it will get me started. |
|
|
| eric |
|
|
|
|
|
|
| From pgsql-performance-owner@postgresql.org Tue Oct 29 15:13:46 2002 |
| Received: from localhost (postgresql.org [64.49.215.8]) |
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| for <pgsql-performance@postgresql.org>; Tue, 29 Oct 2002 15:13:41 -0500 |
| Date: Tue, 29 Oct 2002 15:13:41 -0500 |
| From: Andrew Sullivan <andrew@libertyrms.info> |
| To: pgsql-performance@postgresql.org |
| Subject: Re: Low Budget Performance |
| Message-ID: <20021029151341.S25851@mail.libertyrms.com> |
| Mail-Followup-To: Andrew Sullivan <andrew@libertyrms.info>, |
| pgsql-performance@postgresql.org |
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|
|
| On Tue, Oct 29, 2002 at 10:43:33AM -0800, eric soroos wrote: |
| > Is a scsi system that much better? Looking at prices, scsi is 1/2 |
| > the capacity and double the price for the 80 gig 7200rpm ide vs 36 |
| > gig 10k rpm scsi. Assuming that I'll never run out of space before |
| > running out of performance, I can dedicate 2x the number of ide |
| > drives to the problem. |
| |
| SCSI is dramatically better at using the interface. It is much |
| smarter about, for instance, handling multiple disks at the same |
| time; and it requires less attention from the CPU. |
| |
| That said, if you have enough high speed IDE controllers and disks, |
| you'll probably beat an older SCSI system. And you can't beat the |
| price/performance of IDE RAID. We use it for some applications. |
| |
| Note also that you get better RAID controllers from SCSI vendors, |
| just because it's the official high speed offering. The Promise IDE |
| RAID is nice, but it sure isn't as fast as the latest SCSI RAID |
| controllers. (We have also found that there's some overhead in the |
| IDE RAID. It was better under FreeBSD than I'm now experiencing |
| under Linux. But that might just be my prejudices showing!) |
| |
| A |
| -- |
| ---- |
| Andrew Sullivan 204-4141 Yonge Street |
| Liberty RMS Toronto, Ontario Canada |
| <andrew@libertyrms.info> M2P 2A8 |
| +1 416 646 3304 x110 |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 29 16:09:50 2002 |
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| Tue, 29 Oct 2002 16:09:43 -0500 |
| Subject: Re: Low Budget Performance |
| From: Ron Johnson <ron.l.johnson@cox.net> |
| To: pgsql-performance@postgresql.org |
| In-Reply-To: <20021029123110.M25851@mail.libertyrms.com> |
| References: <200210290807.50625.mweilguni@sime.com> |
| <web-1803616@davinci.ethosmedia.com> |
| <20021029123110.M25851@mail.libertyrms.com> |
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| |
| On Tue, 2002-10-29 at 11:31, Andrew Sullivan wrote: |
| > On Tue, Oct 29, 2002 at 09:10:31AM -0800, Josh Berkus wrote: |
| > > |
| > > Out of curiousity, what is it with RAID 5? I've encountered the poor |
| > > write performance too ... any idea why? |
| > |
| > It largely depends on the controller and te implementation. It has |
| > to do with the cost of calculating the checksum. If the |
| > implementation of that is inefficient, the writes become inefficient. |
|
|
| A high-quality smart controller with lots of cache RAM definitely |
| negates the RAID5 performance issues. |
|
|
| (Of course, I'm referring to enterprise-level rack-mounted h/w |
| that costs big bucks...) |
| |
| -- |
| +------------------------------------------------------------+ |
| | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | |
| | Jefferson, LA USA http://members.cox.net/ron.l.johnson | |
| | | |
| | "they love our milk and honey, but preach about another | |
| | way of living" | |
| | Merle Haggard, "The Fighting Side Of Me" | |
| +------------------------------------------------------------+ |
| |
| |
| From pgsql-performance-owner@postgresql.org Tue Oct 29 16:57:30 2002 |
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| From: "Robert J. Sanford, Jr." <rsanford@trefs.com> |
| To: <pgsql-performance@postgresql.org> |
| Subject: Re: Low Budget Performance |
| Date: Tue, 29 Oct 2002 15:57:29 -0600 |
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| |
| > -----Original Message----- |
| > From: pgsql-performance-owner@postgresql.org |
| > [mailto:pgsql-performance-owner@postgresql.org] |
| > On Behalf Of Ron Johnson |
| > Sent: Tuesday, October 29, 2002 3:10 PM |
| > To: pgsql-performance@postgresql.org |
| > Subject: Re: [pgsql-performance] Low Budget Performance |
| > |
| > |
| > On Tue, 2002-10-29 at 11:31, Andrew Sullivan wrote: |
| > > On Tue, Oct 29, 2002 at 09:10:31AM -0800, Josh Berkus |
| > > wrote: |
| > > > |
| > > > Out of curiousity, what is it with RAID 5? I've |
| > > > encountered the poor write performance too ... any |
| > > > idea why? |
| > > |
| > > It largely depends on the controller and the |
| > > implementation. It has to do with the cost of |
| > > calculating the checksum. If the implementation of |
| > > that is inefficient, the writes become inefficient. |
| > |
| > A high-quality smart controller with lots of cache RAM |
| > definitely negates the RAID5 performance issues. |
| > |
| > (Of course, I'm referring to enterprise-level rack-mounted |
| > h/w that costs big bucks...) |
| |
| Only if you buy it new. EBay has some great deals these days. My company |
| just purchased a very nice Quad Xeon w/ 2GB RAM and last year's high-end |
| PERC RAID controller for under $5K. The external drive array was a bit more |
| expensive but that is an optional purchase. The 3x9GB SCSI drives that came |
| with the machine should be more than sufficient to run a greater than small |
| database server. If you don't want to spend $5K there are Dual Xeon machines |
| with less RAM and not quite so nice RAID controllers that you can get in the |
| $2.5K to $3.5K range. |
| |
| rjsjr |
| |
| |
| From pgsql-performance-owner@postgresql.org Wed Oct 30 20:38:52 2002 |
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| Message-ID: <3DC089A4.7B6D3B9E@postgresql.org> |
| Date: Thu, 31 Oct 2002 12:38:45 +1100 |
| From: Justin Clift <justin@postgresql.org> |
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| To: josh@agliodbs.com |
| Cc: pgsql-performance@postgresql.org |
| Subject: Re: PG_Autotune 0.1 |
| References: <200210151100.58044.josh@agliodbs.com> |
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| |
| Josh Berkus wrote: |
| > |
| > Folks, Justin, |
| > |
| > Hey, I've been tinkering with PG_autotune in an effort to make it usable on my |
| > installation. |
| > http://gborg.postgresql.org/project/pgautotune/projdisplay.php |
| > |
| > First off, thank you Justin for getting inspired and writing the starter |
| > version. This is something that would probably have remained *way* down the |
| > Postgres TODO list, were it not for you. |
|
|
| Thats cool. :) |
|
|
| > Since it's such a great idea, I'd like to make it bulletproof so that it can |
| > become part of the standard Postgres distribution. I'm hoping that people |
| > on this list can help. |
| |
| Hopefully. :) |
| |
| > Problems, Bugs, & Suggestions: |
| > 1) The program makes the assumption that the Postgres superuser is named |
| > "pgsql", forcing me to do a search-and-replace on the source to make it work |
| > at all on my system, where the superuser is named "postgres". This should |
| > be a configuration option. Places I've identified where this is an issue: |
| > a. the connection to the "metrics" database, b. the calls to Postgres |
| > executables (which are also sometimes made as the console user, causing them |
| > to fail if you run the program as "root"). |
|
|
| Good point. It was developed on FreeBSD, and the PostgreSQL superuser |
| on FreeBSD (using the default installation method) is called "pgsql". |
| On at least Solaris and Linux the most common name for the superuser |
| appears to be "postgres". |
|
|
| > 2) The program also assumes that all Postgres binaries are symlinked in |
| > /usr/local/bin. Since this symlinking isn't done by Postgres-make-install, |
| > wouldn't it be better to reference $PGHOME/bin? |
|
|
| Yep. |
|
|
| > 3) For that matter, it would be nice if the program would test $PGDATA and |
| > $PGHOME, and prompt the user if they are empty. |
|
|
| Good point. |
|
|
| > 4) The shell scripts need to have error-checking so that they exit if anything |
| > blows up. I can write this if Justin can explain what the shell scripts are |
| > supposed to do, exactly, and where errors are acceptable. |
|
|
| Ok, no problem. |
|
|
| There are really only two shell scripts and a template. Forgot to |
| include the template i n the downloadable version. :( Have to fix that |
| soon. |
|
|
| The shell scripts all reside in the $PGDATA directory and work like |
| this: |
|
|
| 1) The main shell script is called by the pg_autotune executable, and |
| all it does is adjust the settings for a couple of variables in the |
| postgresql.conf file. At present the variables it adjusts are |
| max_connections, sort_mem, vacuum_mem and shared_buffers. Others could |
| definitely be added in, but this is a start. The method used for |
| adjusting the variables is to have a template postgresql.conf file with |
| tokens for the settings to be replaced, and then parsing them with sed |
| or awk or something. Can't remember offhand how, but I do remember it |
| was a quick&ugly hack. :-/ Needs to be done properly down the track. |
| |
| 2) Restarts the PostgreSQL database (pg_ctl stop; pg_ctl start). Sure, |
| long approach, but it works reliably. :) |
| |
| 3) The second shell script exists only to catch the output from the |
| "pg_ctl start" command and then exit, as if you don't pipe the output to |
| a valid process then the "pg_ctl start" doesn't appear to work |
| properly. This was the only way I could see that would consistently |
| work and not leave open filehandles around. |
| |
| > 5) We need installation docs. I can write these. Sometime soon, really! |
| |
| Cool. Lets do it. :) |
| |
| |
| > Questions & Suggestions for Enhancement: |
| > |
| > 6) The shared_buffers param is capped at 500. Isn't this awfully low for a |
| > production server? What's the logic here? |
| |
| They're just values that were ok to test with whilst making the program |
| work. |
|
|
| > 7) Any ideas on how to get around/adjust memory maximums for the host OS? |
| > This is easy on Linux, but other *nixes are not so easy. |
|
|
| Probably the best approach initially is to detect memory failure related |
| errors where possible and then advise the user how to adjust them. |
| Pointing to the relevant section of the PostgreSQL manual in the |
| PostgreSQL Interactive Docs might be the way to go here. |
|
|
|
|
| > 8) What will be the difficulties in expanding the script to adjust more |
| > Postgresql.conf params, such as checkpoint_segments? Can we use feedback |
| > from the log to adjust these? |
|
|
| Good idea. As this tool is a reasonably brute force tester, the more |
| parameters added could increase the time needed for testing, unless |
| someone comes up with some bright ideas. :) |
|
|
| > 9) I *love* the idea of letting the benchmarking script run custom queries. |
| > However, I would dearly like to expand it, letting it randomly grab from a |
| > list of 10 custom queries entered by the user into a file or files. This |
| > would allow the user to create a realistic mix of simple and complex queries, |
| > including some data manipulation and procedures. |
|
|
| Hey good idea. The section of the code in place for letting the user |
| run custom queries isn't yet finished, but it wouldn't take a |
| half-decent coder long to do. |
|
|
|
|
| > 10) Can we eventually adjust the program to get feedback from system tools and |
| > give the user hints on hardware limitations? For example, have the program |
| > test if, at maximum settings, queries are slow but CPU and RAM are only 10% |
| > utilized and tell the user "Your hard drives are probably too slow"? |
|
|
| Very good thought, and very worthwhile. Any idea how to start with it? |
|
|
|
|
| > I can help with: documentation, shell scripting, Linux system issues. Other |
| > volunteers to help? |
|
|
| Hopefully. |
|
|
| :) |
|
|
| Regards and best wishes, |
|
|
| Justin Clift |
|
|
| > |
| > -Josh Berkus |
| > Aglio Database Solutions |
| > San Francisco |
| > |
| > |
| > TIP 5: Have you checked our extensive FAQ? |
| > |
| > http://www.postgresql.org/users-lounge/docs/faq.html |
|
|
| |
| "My grandfather once told me that there are two kinds of people: those |
| who work and those who take the credit. He told me to try to be in the |
| first group; there was less competition there." |
| - Indira Gandhi |
|
|
|
|
