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Message-ID: <603c8f070812170618g3116a90du94cbf102f0336d59@mail.gmail.com>
Date: Wed, 17 Dec 2008 09:18:54 -0500
From: "Robert Haas" <robertmhaas@gmail.com>
To: "Jaime Casanova" <jcasanov@systemguards.com.ec>
Subject: Re: measure database contention
Cc: "psql performance list" <pgsql-performance@postgresql.org>
In-Reply-To: <3073cc9b0812161132w3ae157a8n69e2b0cccea05ca2@mail.gmail.com>
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References: <3073cc9b0812161132w3ae157a8n69e2b0cccea05ca2@mail.gmail.com>

On Tue, Dec 16, 2008 at 2:32 PM, Jaime Casanova
<jcasanov@systemguards.com.ec> wrote:
> we have a some bad queries (developers are working on that), some of
> them run in 17 secs and that is the average but when analyzing logs i
> found that from time to time some of them took upto 3 mins (the same
> query that normally runs in 17secs).
>
> so my question is: how could i look for contention problems?

Is it the exact same query?  Sometimes you might find that the query
plan changes depending on the particular values you have in there; it
is worth running "EXPLAIN ANALYZE" to look for such cases.

You might also want to look at pg_locks.

...Robert