From: Murthy Nunna <mnunna@fnal.gov>
To: pgsql-admin@postgresql.org <pgsql-admin@postgresql.org>
Subject: Intermittent Query Performance Issue
Date: Fri, 19 Apr 2024 17:02:41 +0000
Message-ID: <DM8PR09MB66772143CBEAD3538AB98906B80D2@DM8PR09MB6677.namprd09.prod.outlook.com> (raw)
Hi,
I am running pg 14.4
I have a simple query :
select max(c) from tab1 where name = 'xxx' ;
This query runs some times very slow. It takes about 40 minutes.
Most of the time it completes in few seconds.
When it runs slow, wait_event in pg_stat_activity shows "DataFileRead". Obviously, it is reading from file storage and that is why it is taking so long.
This is a big table 512GB. It has some child tables.
Is there a way I can reproduce the slowness at will, so I can attempt to tune it? Or any ideas I can try to fix the issue? I hate to try something not knowing if the problem is fixed or not. That is the reason I would like to reproduce the issue first.
Thank you all!
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To: pgsql-admin@postgresql.org
Cc: mnunna@fnal.gov
Subject: Re: Intermittent Query Performance Issue
In-Reply-To: <DM8PR09MB66772143CBEAD3538AB98906B80D2@DM8PR09MB6677.namprd09.prod.outlook.com>
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