Re: Index scan is not working, why??

From: Mladen Gogala <mladen(dot)gogala(at)vmsinfo(dot)com>
To: AI Rumman <rummandba(at)gmail(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Index scan is not working, why??
Date: 2010-10-21 13:27:44
Message-ID: 4CC03FD0.80003@vmsinfo.com
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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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