From: Scott Marlowe <smarlowe@g2switchworks.com>
To: Michael Fuhr <mike@fuhr.org>
Cc: Richard Huxton <dev@archonet.com>
Cc: Jozsef Szalay <jszalay@storediq.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Incorrect Total runtime Reported by Explain Analyze!?
Date: Thu, 26 Jan 2006 11:59:49 -0600
Message-ID: <1138298389.22740.11.camel@state.g2switchworks.com> (raw)
In-Reply-To: <20060126175723.GA83137@winnie.fuhr.org>
References: <E387E2E9622FDD408359F98BF183879E2BDE92@dc1.storediq.com>
<43D8FDB7.10905@archonet.com>
<20060126175723.GA83137@winnie.fuhr.org>
On Thu, 2006-01-26 at 11:57, Michael Fuhr wrote:
> On Thu, Jan 26, 2006 at 04:49:59PM +0000, Richard Huxton wrote:
> > Jozsef Szalay wrote:
> > >I have seen it on occasion that the total runtime reported by explain
> > >analyze was much higher than the actual time the query needed to
> > >complete. The differences in my case ranged between 20-120 seconds. I'm
> > >just curious if anyone else has experienced this and whether there is
> > >something that I can do to convince explain analyze to report the
> > >execution time of the query itself rather than the time of its own
> > >execution. Engine version is 8.1.1.
> >
> > I think it's down to all the gettime() calls that have to be made to
> > measure how long each stage of the query takes. In some cases these can
> > take a substantial part of the overall query time.
>
> Another possibility is that the total query time was indeed that
> long because the query was blocked waiting for a lock. For example:
Could be, but I've had this happen where the query returned in like 1
second but reported 30 seconds run time.
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To: pgsql-performance@postgresql.org
Cc: smarlowe@g2switchworks.com, mike@fuhr.org, dev@archonet.com, jszalay@storediq.com
Subject: Re: Incorrect Total runtime Reported by Explain Analyze!?
In-Reply-To: <1138298389.22740.11.camel@state.g2switchworks.com>
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