From: kimaidou [mailto:kimaidou@gmail.com] Sent: Friday, February 22, 2019 10:37 AM To: pgsql-performance@lists.postgresql.org Subject: Slow query with aggregate and many LEFT JOINS
Hi all,
I need to optimize the following query http://paste.debian.net/hidden/ef08f864/ I use it to create a materialized view, but I think there is room for optimization. I tried to SET join_collapse_limit TO 15; with to real difference.
Explain shows that the GROUP AGGREGATE and needed sort kill the performance. Do you have any hint how to optimize this ? https://explain.depesz.com/s/6nf
Regards Michaël
Try increasing both: join_collapse_limit and from_collapse_limit to 16 (or even 17).
