From: Simon Riggs <simon@2ndquadrant.com>
To: hubert depesz lubaczewski <depesz@gmail.com>
Cc: PostgreSQL General <pgsql-general@postgresql.org>
Cc: pgsqlperform <pgsql-performance@postgresql.org>
Subject: Re: [PERFORM] database bloat, but vacuums are done, and fsm seems
Date: Mon, 03 Oct 2005 22:47:02 +0100
Message-ID: <1128376022.8603.137.camel@localhost.localdomain> (raw)
In-Reply-To: <9e4684ce05092800075d37d0cc@mail.gmail.com>
References: <9e4684ce05092800075d37d0cc@mail.gmail.com>
On Wed, 2005-09-28 at 09:07 +0200, hubert depesz lubaczewski wrote:
> database has quite huge load of updates, but i thought that vacum will
> guard me from database bloat, but from what i observed it means that
> vacuuming of b-tree indices is somewhat faulty.
No, thats perfectly normal.
Indices are packed tighter when they are first created and they spread
out a bit as you update the database. Blocks start at 90% full and end
up at 50% full for non-monotonic indexes (e.g. SERIAL) or 67% for
monotonic.
It's a long debated design feature on any DBMS that uses b-trees.
REINDEX or dump/restore should be identical.
Best Regards, Simon Riggs
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To: pgsql-performance@postgresql.org
Cc: simon@2ndquadrant.com, depesz@gmail.com, pgsql-general@postgresql.org
Subject: Re: [PERFORM] database bloat, but vacuums are done, and fsm seems
In-Reply-To: <1128376022.8603.137.camel@localhost.localdomain>
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