From: Tom Lane <tgl@sss.pgh.pa.us>
To: stange@rentec.com
Cc: Vivek Khera <vivek@khera.org>
Cc: Postgresql Performance <pgsql-performance@postgresql.org>
Subject: Re: postgresql performance tuning
Date: Tue, 06 Dec 2005 16:20:57 -0500
Message-ID: <16451.1133904057@sss.pgh.pa.us> (raw)
In-Reply-To: <4395F914.8070001@rentec.com>
References: <Pine.LNX.4.58.0512060941090.21795@karadi.cs.wisc.edu>
<F069CC64-C748-4EC1-ADF3-38D2FBC230CD@khera.org>
<4395F914.8070001@rentec.com>
Alan Stange <stange@rentec.com> writes:
> Vivek Khera wrote:
>> what evidence do you have that you are suffering index bloat?
> The files for the two indices on a single table used 7.8GB of space
> before a reindex, and 4.4GB after.
That's not bloat ... that's pretty nearly in line with the normal
expectation for a btree index, which is about 2/3rds fill factor.
If the compacted index were 10X smaller then I'd agree that you have
a bloat problem.
Periodic reindexing on this scale is not doing a lot for you except
thrashing your disks --- you're just giving space back to the OS that
will shortly be sucked up again by the same index.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, stange@rentec.com, vivek@khera.org
Subject: Re: postgresql performance tuning
In-Reply-To: <16451.1133904057@sss.pgh.pa.us>
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