From: | Martín Marqués <martin(at)bugs(dot)unl(dot)edu(dot)ar> |
---|---|
To: | Linh Luong <linh(dot)luong(at)computalog(dot)com>, pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Seq Scan |
Date: | 2001-05-28 12:46:20 |
Message-ID: | 01052815462000.01658@bugs |
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Thread: | |
Lists: | pgsql-sql |
On Lun 28 May 2001 19:24, Linh Luong wrote:
> Hi,
>
> I am trying to execute this query I wrote and it is not returning at a
> reasonable time to the browser. I took the query and ran EXPLAIN on it
> and it displayed that every JOIN I do it is doing a Seq Scan on it. I
> have indexes on that table but it doesn't seem to use it.
>
> Is there a way I can ensure that postgres will use my indexes?
When Postgres doesn´t use indexes, it´s because sequencial scans are faster
(I think the normal case would be a table with not so much rows).
AFAIK, the planer is who does this, and it uses internal data which was
gathered during a VACUUM analyze.
So I would do a VACUUM analyze and the re-run the EXPLAIN to see what it
shows.
Saludos... :-)
--
Cualquiera administra un NT.
Ese es el problema, que cualquiera administre.
-----------------------------------------------------------------
Martin Marques | mmarques(at)unl(dot)edu(dot)ar
Programador, Administrador | Centro de Telematica
Universidad Nacional
del Litoral
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