Re: Optimizing a request

----- Original Message -----
From: Gary Doades <gpd@gpdnet.co.uk>
Date: Tue, 31 Aug 2004 20:21:49 +0100
Subject: Re: [PERFORM] Optimizing a request
To: pgsql-performance@postgresql.org



> Have you run ANALYZE on this database after creating the indexes or loading the data?

the indexes are created and the data loaded and then, I run vacuum analyze.

>What percentage of rows in the "article" table are likely to match
the keys selected from  the "rubrique" table?

only 1 record.

If it is likely to fetch a high proportion of the rows from article
then it may be best that a seq scan is performed.

What are your non-default postgresql.conf settings? It may be better
to increase the default_statistics_target (to say 100 to 200) before
running ANALYZE and then re-run the query.

yes,  default_statistics_target is set to the default_value.
I have just increased  shared_buffers and effective_cache_size to give
advantage of 1 Mb RAM




--
Jean-Max Reymond
CKR Solutions
http://www.ckr-solutions.com