Re: [PERFORM] optimizing query

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Chantal Ackermann <chantal(dot)ackermann(at)biomax(dot)de>, Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com>, pgsql-general(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] optimizing query
Date: 2003-01-27 00:54:25
Message-ID: 200301270054.h0R0sP721325@candle.pha.pa.us
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Tom Lane wrote:
> > postgresql.conf:
> > shared_buffers: 121600
> > max_connections: 64
> > max_fsm_relations = 200
> > max_fsm_pages = 40000
> > effective_cache_size = 8000
>
> Try increasing sort_mem.
>
> Also, I'd back off on shared_buffers if I were you. There's no evidence
> that values above a few thousand buy anything.

Increasing shared_buffers above several thousand will only be a win if
your entire working set will fit in the larger buffer pool, but didn't
in the previous size. If you working set is smaller or larger than
that, pushing it above several thousand isn't a win. Is that a more
definitive answer?

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