Re: Slow SQL query (14-15 seconds) - Mailing list pgsql-performance

From Matthew Wakeling
Subject Re: Slow SQL query (14-15 seconds)
Date
Msg-id alpine.DEB.1.10.0811131321110.4666@aragorn.flymine.org
Whole thread Raw
In response to Slow SQL query (14-15 seconds)  (Bruno Baguette <bruno.baguette@gmail.com>)
Responses Re: Slow SQL query (14-15 seconds)  (Bruno Baguette <bruno.baguette@gmail.com>)
List pgsql-performance
On Thu, 13 Nov 2008, Bruno Baguette wrote:
> I'm having a problem with this query (below) that takes between 14 and 15
> seconds to run, which is too long for the end-user.
>
> I've done a EXPLAIN ANALYZE (below below) but I'm having difficulties to see
> which part of that query is taking so many times.

As a general tip, if you're trying to work out which part of a query is
taking time, and the query is fairly obviously made up of several parts,
it would make sense to try them individually.

In any case, it appears that the time is being taken performing a full
index scan over the societe table, in one of the subqueries. Perhaps you
could run each of the subqueries individually, and send us the one that
takes loads of time as a simpler problem to solve.

Matthew

--
Those who do not understand Unix are condemned to reinvent it, poorly.
                -- Henry Spencer

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