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Re: Vacuum Problems (locking)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Mike Goldner <mgoldner(at)agmednet(dot)com>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: Vacuum Problems (locking)
Date: 2006-10-25 22:30:51
Message-ID: 5751.1161815451@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-admin
Mike Goldner <mgoldner(at)agmednet(dot)com> writes:
> First of all, my max_fsm_pages is obviously way off.  However, every
> time I increase my max_fsm_pages the next vacuum says that it requires
> more.  Will there every be a plateau in the requested pages?

We realized recently that this can happen if you have a single relation
that all by itself needs more FSM space than you've got; any per-table
space beyond max_fsm_pages is disregarded in the calculation of the
total system-wide space needed, and so you get this inflationary effect
where the reported requirement keeps going up when you increase the
setting.  There's a fix in for 8.2.

> So, all indications point to postgres blocking all access during the
> entire vacuum.  

You haven't said anything I consider credible evidence of that.  But try
looking in pg_locks next time.

			regards, tom lane

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Subject: Re: CLUSTER using more memory than expected
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