Re: Incorrect Total runtime Reported by Explain Analyze!? - Mailing list pgsql-performance

From Richard Huxton
Subject Re: Incorrect Total runtime Reported by Explain Analyze!?
Date
Msg-id 43D8FDB7.10905@archonet.com
Whole thread Raw
In response to Incorrect Total runtime Reported by Explain Analyze!?  ("Jozsef Szalay" <jszalay@storediq.com>)
Responses Re: Incorrect Total runtime Reported by Explain Analyze!?
List pgsql-performance
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. I seem to recall one
of the BSDs was particularly bad in this respect a couple of years ago.
Does that sound like your problem?

--
   Richard Huxton
   Archonet Ltd

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