Re: EXPLAIN ANALYZE total runtime != walltime

Stephan Szabo wrote:
> On Wed, 25 Aug 2004, Jon Lapham wrote:
>
>
>>I have been using the EXPLAIN ANALYZE command to debug some performance
>>bottlenecks in my database. In doing so, I have found an oddity (to me
>>anyway). The "19ms" total runtime reported below actually takes 25
>>seconds on my computer (no other CPU intensive processes running). Is
>>this normal for EXPLAIN ANALYZE to report a total runtime so vastly
>>different from wall clock time?
>>
>>During the "explain ANALYZE delete from msgid;" the CPU is pegged at
>>100% for the postmaster process, and the HD light only flashes
>>intermittently, so I do not think it is HD I/O.
>>
>>I tossed in a "EXPLAIN ANALYZE VERBOSE" at the end of this email, in
>>case that helps anyone.
>
>
> I think EXPLAIN ANALYZE time doesn't include after trigger time (for
> example for foreign keys). Do any tables reference this one?

Yup, I have a referencing table, that is indeed the performance problem.
I'm just surprised that the "total runtime" is not the.. well... total
runtime. :)

Thanks,
Jon

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Jon Lapham <lapham(at)jandr(dot)org> Rio de Janeiro, Brasil
Personal: http://www.jandr.org/
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