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List:       postgresql-general
Subject:    Re: [GENERAL] Autovacuum not vacuuming pg_largeobject
From:       Ron Mayer <rm_pg () cheapcomplexdevices ! com>
Date:       2007-08-30 21:24:41
Message-ID: 46D73599.4090700 () cheapcomplexdevices ! com
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Denis Gasparin wrote:
>> Yeah, you're wrong.  The difference is that plain vacuum does not try
>> very hard to reduce the length of a table file --- it just frees up
>> space within the file for reuse.  vacuum full will actually move things
>> from the end of the file to free space nearer the head of the file,
>> so that it can shorten the file.
>>
>> What I suspect the above observations really prove is you don't have
>> max_fsm_pages set high enough, and so pg_largeobject was bloating because
>> the free space was being forgotten instead of reused.
>>
>>   
> I tried to issue the vacuum command on one of my database and i got the
> following log messages:
> 
> LOG:  max_fsm_relations(1000) equals the number of relations checked
> HINT:  You have at least 1000 relations.  Consider increasing the
> configuration parameter
> 
> I suspect I must increase max_fsm_relations.
> The value of max_fsm_pages is 20000 (the default value).
> I suspect I must change this to a higher value... but how high should
> this value be?


First increase max_fsm_relations to more than the number of tables,etc
in your system.   Then, after it's running a while, do the same vacuum
command and see if it gives you a hint to increase that parameter too.

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TIP 5: don't forget to increase your free space map settings
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