Re: [GENERAL] how to get accurate values in pg_statistic

From: Rod Taylor <rbt(at)rbt(dot)ca>
To: Mary Edie Meredith <maryedie(at)osdl(dot)org>
Cc: pgsql-performance <pgsql-performance(at)postgresql(dot)org>, OSDL - DB General <osdldbt-general(at)lists(dot)sourceforge(dot)net>
Subject: Re: [GENERAL] how to get accurate values in pg_statistic
Date: 2003-09-04 17:46:47
Message-ID: 1062697606.88158.7.camel@jester
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On Thu, 2003-09-04 at 13:41, Mary Edie Meredith wrote:
> Our port of OSDL DBT3 test suite to PostgreSQL (see Background
> information below) is nearing completion. We would also like to confirm
> our understanding of an outstanding consistency issue.
>
> We have not been able to do meaningful kernel testing since the runs
> (all parameters/kernels being equal) arewildly varying - sometimes
> 20-25% differences in the metrics run to run.

Run a VACUUM FULL ANALYZE between runs. This will force a full scan of
all data for stats, as well as ensure the table is consistently
compacted.

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