Re: Write-heavy pg_stats_collector on mostly idle server

Hi Josh,

it's "known" issue, see this thread:

http://archives.postgresql.org/pgsql-hackers/2010-02/thrd6.php#01290

HTH,

Kuba

Dne 8.2.2011 2:39, Josh Berkus napsal(a):
>
>> Ooops.
>> It looks like you are right, see ./src/backend/postmaster/pgstat.c
>>
>> 3c2313f4 (Tom Lane           2008-11-03 01:17:08 +0000 2926)
>>   if (last_statwrite<  last_statrequest)
>> 70d75697 (Magnus Hagander    2008-08-05 12:09:30 +0000 2927)
>>           pgstat_write_statsfile(false);
>
> This is a different issue.  This is happening because we have a bunch of
> databases (25 to 35) and as a result autovacuum is requesting the stats
> file rather frequently.  And autovacuum for whatever reason won't accept
> a stats file more than 10ms old, so it pretty much rewrites the stats
> file on every request.
>
> At least, that's my reading of it after poking around and talking to
> Gierth.
>
> It seems like that 10ms window for autovac is way too small.
>