Re: Incorrect Total runtime Reported by Explain Analyze!?

It might be. I'm running on Fedora Linux kernel 2.6.5-1.358smp, GCC
3.3.3, glibc-2.3.3-27


-----Original Message-----
From: Richard Huxton [mailto:dev@archonet.com]
Sent: Thursday, January 26, 2006 10:50 AM
To: Jozsef Szalay
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Incorrect Total runtime Reported by Explain
Analyze!?

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