Re: Check explain plan of a running query in other session - Mailing list pgsql-novice

From Laurenz Albe
Subject Re: Check explain plan of a running query in other session
Date
Msg-id f83f7705b465f87b07da6ffe57809cc305d1881f.camel@cybertec.at
Whole thread Raw
In response to Check explain plan of a running query in other session  (Jonas Gassenmeyer <gassenmj@gmail.com>)
List pgsql-novice
On Mon, 2021-11-08 at 09:20 +0100, Jonas Gassenmeyer wrote:
> I am asking myself for a while if there is an easy option (via dictionary views like
> pg_stat_activity or similar) to check what execution plan was chosen for a long
> running SQL statement while it is running in a different session?
> I have a performance problem in a plpgsql procedure that executes an update within
> a loop. My guess is that it chose a generic plan instead of bind peeking and then
> does not use an index.
> 
> I am not able to proof my theory, since I don't know how to get the explain plan for it.
> For me the easiest would be to check the running statement in a different session and
> "hook into" the other plpgsql session to check what the optimizer chose.
> 
> Is that something I can do easily? If not: What is the PostgreSQL way of doing it?

There is nothing like that built into PostgreSQL, but you could try pg_show_plans:
https://github.com/cybertec-postgresql/pg_show_plans

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com




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