From: | Cédric Villemain <cedric(dot)villemain(dot)debian(at)gmail(dot)com> |
---|---|
To: | Josh Berkus <josh(at)agliodbs(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Write-heavy pg_stats_collector on mostly idle server |
Date: | 2011-02-05 22:15:15 |
Message-ID: | AANLkTinpWWrDHR9KJNebgtbvpXpL4UdQszD0GxF+FWWu@mail.gmail.com |
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Lists: | pgsql-performance |
2011/2/4 Josh Berkus <josh(at)agliodbs(dot)com>:
> All,
>
> Seeing an issue which is new on me. On a mostly idle PostgreSQL server,
> the stats collector is rewriting the entire stats file twice per second.
>
> Version: 8.4.4
> Server: Ubuntu, kernel 2.6.32
> Server set up: ApacheMQ server. 25 databases, each of which hold 2-3
> tables.
> Filesystem: Ext4, defaults
> Active connections: around 15
> Autovacuum settings: defaults
>
> Symptoms: on a server which gets around 20 reads and 15 writes per
> minute, we are seeing average 500K/second writes by the stats collector
> to pg_stat.tmp. pg_stat.tmp is around 270K.
>
> An strace of the stats collector process shows that the stats collector
> is, in fact, rewriting the entire stats file twice per second.
>
> Anyone seen anything like this before?
>
it is the expected behavior, IIRC
--
Cédric Villemain 2ndQuadrant
http://2ndQuadrant.fr/ PostgreSQL : Expertise, Formation et Support
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