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Re: is pg_autovacuum so effective ?

From: Gaetano Mendola <gmendola(at)mbigroup(dot)it>
To: Markus Schaber <schabios(at)logi-track(dot)com>
Cc: Gaetano Mendola <mendola(at)bigfoot(dot)com>,"Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>,pgsql-performance(at)postgresql(dot)org
Subject: Re: is pg_autovacuum so effective ?
Date: 2005-02-24 22:30:06
Message-ID: 421E556E.6010202@mbigroup.it (view raw or flat)
Thread:
Lists: pgsql-performance
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Markus Schaber wrote:
> Hi, Gaetano,
> 
> Gaetano Mendola schrieb:
> 
> 
>>I have the same requirement too. Actually pg_autovacuum can not be
>>instructed "per table" so some time the global settings are not good
>>enough. I have a table of logs with 6 milions rows ( 3 years logs )
>>I insert on that page ~ 6000 rows for day. I'm running pg_autovacuum
>>with setting to ANALYZE or VACUUM table if the 10% is touched.
>>With this setting pg_autovacuum will analyze that table each 3 months!!!
> 
> 
> If you have only inserts, and only so few on a large table, you do not
> need to vacuum such often. Not to reclaim space, only to prevent
> transaction ID wraparound (which is ensured by pg_autovacuum).
> 
> And if the data distribution does not change, frequently calling ANALYZE
> does not help much, either.

Yes, I'm  aware about it indeed I need the analyze because usualy I do on that
table select regarding last 24 ours so need to analyze it in order to
collect the statistics for this period.
Beside that I tried to partition that table, I used both tecnique on
my knowledge

1) A view with UNION ALL on all tables collecting these logs
2) Using inheritance

and both cases are working in theory but in practice are not ( the index scan
is lost as soon you use this view/table inside others views or joining them)

I heard that next version of pg_autovacuum can be instructed "per table";
is it true ?


Regards
Gaetano Mendola










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