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Re: indexed column but queries still slow

From: Gaetano Mendola <mendola(at)bigfoot(dot)com>
To: Amir Zicherman <amir(dot)zicherman(at)gmail(dot)com>
Subject: Re: indexed column but queries still slow
Date: 2004-08-17 23:28:29
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Lists: pgsql-novice
Amir Zicherman wrote:

 > hi,
 > i have a btree index on col1 in table1.  The column has either values
 > 1,2,3, or 4.  4 does not appear that much in the table (only 5 times).
 >  there are about 20 million rows in the table.  when i do a "select *
 > from table1 where col1=4" it takes very long time to get back to me
 > (around 4 minutes).  why is it taking so long if i have an index on
 > it?  I also tried this with a hash index and it was still slow.

May I see the result of
explain analyze select * from table1 where col1 = 4;

and also the table definition could be usefull.

Did you run recently an analyze on your table ?

Gaetano Mendola

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