Re: cluster test

From: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Gregory Stark <stark(at)enterprisedb(dot)com>, Joachim Wieland <joe(at)mcknight(dot)de>, pgsql-patches(at)postgresql(dot)org
Subject: Re: cluster test
Date: 2007-05-26 10:40:52
Message-ID: 46580EB4.9030308@enterprisedb.com
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Tom Lane wrote:
> Gregory Stark <stark(at)enterprisedb(dot)com> writes:
>> Perhaps this comes down to 64 vs 32 bit datum and aligments and therefore
>> different size tables which because the planner does the lseek to measure the
>> table size shows up as different estimates for sequential scan costs?
>
> But we've got plenty of both in the buildfarm, and none of them are
> showing this failure. So I'm curious to know what's really different
> about Joachim's installation. It seems he must have a pg_constraint
> table enough larger than "normal" to discourage the seqscan, but where
> did that come from? There's only one row in pg_constraint in standard
> template0 --- could he be working with a custom system that has many
> more?

Or maybe some non-default values in postgresql.conf? Like random_page_cost?

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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