From: | Cosimo Streppone <cosimo(at)streppone(dot)it> |
---|---|
To: | Postgresql Performance list <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: faster search |
Date: | 2005-06-11 11:05:55 |
Message-ID: | 42AAC593.4050406@streppone.it |
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Thread: | |
Lists: | pgsql-performance |
Steve Atkins wrote:
> On Fri, Jun 10, 2005 at 01:45:05PM -0400, Clark Slater wrote:
>
>>Hi-
>>
>>Would someone please enlighten me as
>>to why I'm not seeing a faster execution
>>time on the simple scenario below?
>
> [...]
>
> Create an index on (productlistid, typeid, partnumber) then
>
> select * from test where productlistid=3 and typeid=9
> order by productlistid, typeid, partnumber LIMIT 15;
>
Clark, try also adding (just for testing) partnumber to your
where clause, like this:
select * from test where productlistid=3 and typeid=9
and partnumber='foo' order by productlistid,
typeid, partnumber;
and check output of explain analyze.
I had experiences of planner "bad" use of indexes when attribute
types were integer and cardinality was low (a single attribute
value, like "typeid=9" selects one or few rows).
However, this was on 7.1.3, and probably is not relevant to your case.
--
Cosimo
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