Re: indexed column but queries still slow

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 ?

Regards
Gaetano Mendola