From: Tom Lane <tgl@sss.pgh.pa.us>
To: ow <oneway_111@yahoo.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: 7.4 - FK constraint performance
Date: Thu, 12 Feb 2004 23:49:56 -0500
Message-ID: <27696.1076647796@sss.pgh.pa.us> (raw)
In-Reply-To: <20040213012253.64419.qmail@web60807.mail.yahoo.com>
References: <20040213012253.64419.qmail@web60807.mail.yahoo.com>
ow <oneway_111@yahoo.com> writes:
> --- Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Can't see how we optimize your case without pessimizing more-common cases.
> I think other RDBMSs simply use preset value instead of partial table
> scan when there's not enough stat info. Might be a better way.
The problem here cannot be described as "not enough stat info". The
available stats are complete and they point very strongly to the
conclusion that searches in the large table should be seqscans.
To do otherwise would be folly in general, even if it happens to
be the correct thing in this particular example.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, oneway_111@yahoo.com
Subject: Re: 7.4 - FK constraint performance
In-Reply-To: <27696.1076647796@sss.pgh.pa.us>
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