RE: Slow query with aggregate and many LEFT JOINS
| От | Igor Neyman |
|---|---|
| Тема | RE: Slow query with aggregate and many LEFT JOINS |
| Дата | |
| Msg-id | DM5PR17MB15327D949173FD6AD7CC49F1DA7F0@DM5PR17MB1532.namprd17.prod.outlook.com обсуждение исходный текст |
| Ответ на | Slow query with aggregate and many LEFT JOINS (kimaidou <kimaidou@gmail.com>) |
| Ответы |
RE: Slow query with aggregate and many LEFT JOINS
|
| Список | pgsql-performance |
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).
Regards,
Igor Neyman
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