Re: autovacuum not freeing up unused space on 8.3.0

From: Stuart Brooks <stuartb(at)cat(dot)co(dot)za>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: autovacuum not freeing up unused space on 8.3.0
Date: 2008-02-27 13:51:06
Message-ID: 47C56ACA.1020006@cat.co.za
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>>> Are you measuring index as well as table size? VACUUM FULL is no good
>>> at compacting indexes.
>>>
>>>
>> I am measuring pg_total_relation_size which I believe includes indexes.
>> How does one go about compacting indexes if a VACUUM doesn't do the
>> trick? I see that a recommendation is to drop and recreate the indexes.
>> If one has a system running 24-7, then this might not be feasible.
>>
>
> The simplest way is to use REINDEX INDEX, but it needs a strong lock.
>
> The more complex way is to do
>
> CREATE INDEX CONCURRENTLY index_2 ... -- duplicating the original index
> DROP INDEX index;
>
> which does not need to grab a lock for a long period.
>
>

That does the trick and gets the table size down to what I'd expect from
a 'clean' run. Now I just need to run a few tests to work out what a
stable size is for a table with this many rows. Thanks for all the help
tracking this down. It's really appreciated :)

Kind regards
Stuart

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