i was surprised a few weeks ago by this effect.
it seems postgres uses sequential scans for queries when a huge number of
affected rows is expected.
i have read somewhere that it would be slower to use an index in this case.
greetingz
Thilo Hille
resourcery GbR.
Habsburgerstr. 11
79104 Freiburg
Tel.: 0761-4567807
Fax.: 0761-4567805
thilo@resourcery.de
----- Original Message -----
From: Tom Lane <tgl@sss.pgh.pa.us>
To: mila boldareva <pierro@dds.nl>
Cc: <pgsql-novice@postgresql.org>
Sent: Tuesday, August 20, 2002 4:50 PM
Subject: Re: [NOVICE] index is not used
> mila boldareva <pierro@dds.nl> writes:
> > But the indices are not used, even when I added a separate index on
> > field1 !
>
> Have you run ANALYZE (or VACUUM ANALYZE) on that table?
>
> regards, tom lane
>
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