Re: URGENT HELP about 'duration' stats

From: Filip Rembiałkowski <plk(dot)zuber(at)gmail(dot)com>
To: "Camilo Porto" <camiloporto(at)hotmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: URGENT HELP about 'duration' stats
Date: 2007-10-30 16:09:01
Message-ID: 92869e660710300909n4ce1551am9ac105ab9cbea28f@mail.gmail.com
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2007/10/30, Camilo Porto <camiloporto(at)hotmail(dot)com>:

> > > I am simulating only 1 client with the Benchmark. Can 1 Client submit
> > > parallel queries, in single-processor enviroment?
> > If this client uses two connections, you can run two queries in paralell.
> The client uses only 1 connection. In this situation is possible that
> the EXECUTOR's duration time become greater than the time period which the
> Query was observed? (as stated in my first topic)?

I guess it's possible under some circumstances...
2007-10-30 16:07:00 GMT [123] LOG: duration: 99000.000 ms select longfunc()
2007-10-30 16:07:01 GMT [123] LOG: duration: 1000.000 ms select shortfunc()
interval is 1 second, sum of durations 100 seconds :)

AFAIK, timestamps in the front of each line are assigned by log
writer, ie. *in the moment of writing* to the log. I'd better trust
"duration: xxx ms " messages. they are calculated in backend directly.

In this log sample you showed us, the sum of durations is circa 625
ms. and the interval between first and last log entry is circa 822 ms.
If you have a test case which shows that much difference you speak of,
could you please present it here, along with your logging settings?

--
Filip Rembiałkowski

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