Re: backend suddenly becomes slow, then remains slow - Mailing list pgsql-performance

From Tom Lane
Subject Re: backend suddenly becomes slow, then remains slow
Date
Msg-id 5309.1355514960@sss.pgh.pa.us
Whole thread Raw
In response to backend suddenly becomes slow, then remains slow  (Andrew Dunstan <andrew.dunstan@pgexperts.com>)
Responses Re: backend suddenly becomes slow, then remains slow  (Andrew Dunstan <andrew@dunslane.net>)
List pgsql-performance
Andrew Dunstan <andrew.dunstan@pgexperts.com> writes:
> One of my clients has an odd problem. Every so often a backend will
> suddenly become very slow. The odd thing is that once this has happened
> it remains slowed down, for all subsequent queries. Zone reclaim is off.
> There is no IO or CPU spike, no checkpoint issues or stats timeouts, no
> other symptom that we can see. The problem was a lot worse that it is
> now, but two steps have alleviated it mostly, but not completely: much
> less aggressive autovacuuming and reducing the maximum lifetime of
> backends in the connection pooler to 30 minutes.

> It's got us rather puzzled. Has anyone seen anything like this?

Maybe the kernel is auto-nice'ing the process once it's accumulated X
amount of CPU time?

            regards, tom lane


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