From: | "Olaf Mittelstaedt" <mstaedt(at)va-sigi(dot)va(dot)fh-ulm(dot)de> (by way of Herouth Maoz) |
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To: | pgsql-general(at)postgreSQL(dot)org |
Subject: | Re: Index unused with OR? |
Date: | 1998-05-20 13:07:31 |
Message-ID: | l03110706b18885fd4b0d@[147.233.159.109] |
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Lists: | pgsql-general |
> Unrelated to the question in hand - you complained about VACUUM not
> properly updating the stats. It seems to me you should use VACUUM ANALYZE
> for that to happen. Just vacuuming means elimination of old rows no longer
> used.
>
> Herouth
Thanks for your hint, the statistics got updated now with VACUUM
ANALYZE, but indexes aren't used anyway when combining indexed
columns with OR in the WHERE part:
w=> vacuum;
VACUUM
w=> vacuum analyze;
VACUUM
w=> explain select * from p where (m=29000) or (m=30000);
NOTICE: QUERY PLAN:
Seq Scan on p (cost=336.92 size=834 width=10)
EXPLAIN
w=>
Kind regards,
Olaf
--
Olaf Mittelstaedt - IuK - mittelstaedt(at)fh-ulm(dot)de
Fachhochschule Ulm Prittwitzstr. 10 89075 Ulm
Tel.: +49 (0)731-502-8220 Fax: -8270
Tertium non datur.
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