the Unix abort function is called, and a core file is generated.
the database server always behaves in the same manner as abort, except when a device-full fatal error occurs. In this
case, it behaves in the same manner as defunct. This action prevents the system from trying to write a core file on a full
device. This is the default behavior.
the database server continues running and does not call abort. Any new connection attempts made to the database server
receive the SQL error of the original fatal error.