From: Mladen Gogala <mladen.gogala@vmsinfo.com>
To: AI Rumman <rummandba@gmail.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Index scan is not working, why??
Date: Thu, 21 Oct 2010 09:27:44 -0400
Message-ID: <4CC03FD0.80003@vmsinfo.com> (raw)
In-Reply-To: <AANLkTinvBPfo8KcNVEkvt35fEOeO9OREyvq8WpcqbrBg@mail.gmail.com>
References: <AANLkTinvBPfo8KcNVEkvt35fEOeO9OREyvq8WpcqbrBg@mail.gmail.com>
AI Rumman wrote:
> I don't know why seq scan is running on the following query where the
> same query is giving index scan on other servers:
> explain analyze
> select *
> from act
> where act.acttype in ( 'Meeting','Call','Task');
> QUERY PLAN
> ----------------------------------------------------------------------------------------------------------------------------------------
> Seq Scan on act (cost=0.00..13386.78 rows=259671 width=142) (actual
> time=0.013..484.572 rows=263639 loops=1)
> Filter: (((acttype)::text = 'Meeting'::text) OR ((acttype)::text =
> 'Call'::text) OR ((acttype)::text = 'Task'::text))
> Total runtime: 732.956 ms
> (3 rows)
Al, what percentage of the rows fits the above criteria? How big are
your histograms?
--
Mladen Gogala
Sr. Oracle DBA
1500 Broadway
New York, NY 10036
(212) 329-5251
www.vmsinfo.com
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To: pgsql-performance@postgresql.org
Cc: mladen.gogala@vmsinfo.com, rummandba@gmail.com
Subject: Re: Index scan is not working, why??
In-Reply-To: <4CC03FD0.80003@vmsinfo.com>
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