Re: Query performance issue
Greg Sabino Mullane <htamfids@gmail.com>
From: Greg Sabino Mullane <htamfids@gmail.com>
To: yudhi s <learnerdatabase99@gmail.com>
Cc: pgsql-general@lists.postgresql.org, hjp-pgsql@hjp.at
Date: 2024-10-22T19:01:55Z
Lists: pgsql-general
To be frank, there is so much wrong with this query that it is hard to know where to start. But a few top items: * Make sure all of the tables involved have been analyzed. You might want to bump default_statistics_target up and see if that helps. * As mentioned already, increase work_mem, as you have things spilling to disk (e.g. external merge Disk: 36280kB) * Don't use the "FROM table1, table2, table3" syntax but use "FROM table1 JOIN table2 ON (...) JOIN table3 ON (...) * Try not to use subselects. Things like WHERE x IN (SELECT ...) are expensive and hard to optimize. * You have useless GROUP BY clauses in there. Remove to simplify the query * There is no LIMIT. Does the client really need all 135,214 rows? Cheers, Greg