From: siganos@gmail.com (George Siganos)
Subject: Re: Question about a CIDR based query
Date: 26 Jun 2004 16:06:15 -0700
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References: <ebba5a930406241343173046c7@mail.gmail.com>
	<200406250900.08312.josh@agliodbs.com>
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To: pgsql-sql@postgresql.org

I did a vacuum analyze before I run the following explain 

June_03=# explain select * from tmp where route >>='62.1.1.0/24';
                           QUERY PLAN                           
----------------------------------------------------------------
 Seq Scan on tmp  (cost=0.00..606.60 rows=14544 width=33)
   Filter: (route >>= '62.1.1.0/24'::cidr)
(2 rows)

The select returns just one route,
Thanks

josh@agliodbs.com (Josh Berkus) wrote in message news:<200406250900.08312.josh@agliodbs.com>...
> Georgos,
> 
> > select * from tmp where route >>= some_cidr
> 
> Can you post an EXPLAIN ANALYZE for this?   And when's the last time you ran 
> ANALYZE on the table?
> 
> > The index on route is not used and I get a sequential scan. The index is
> > used only for the <<= operator.
> 
> Most likely Postgres thinks that the >>= query is returning 60% of your table, 
> which makes indexes useless.
> 
> -- 
> Josh Berkus
> Aglio Database Solutions
> San Francisco
> 
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