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
DM5PR17MB15323353E29926EE1BC19B04DA7F0@DM5PR17MB1532.namprd17.prod.outlook.com
Ответ на
RE: Slow query with aggregate and many LEFT JOINS (Igor Neyman)
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Дерево обсуждения
Slow query with aggregate and many LEFT JOINS kimaidou <kimaidou@gmail.com>
RE: Slow query with aggregate and many LEFT JOINS Igor Neyman <ineyman@perceptron.com>
RE: Slow query with aggregate and many LEFT JOINS Igor Neyman <ineyman@perceptron.com>
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
Don’t know your hardware config, or Postgres settings,
but I see external disk sort. So, try setting work_mem to ~48MB.
Regards,
Igor Neyman
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