Re: What is syslog:duration reporting ... ?

On Fri, Aug 26, 2005 at 12:50:29AM +0100, Aldor wrote:
> Aug 25 14:53:32 forgehouse-s1 postgres[23721]: [2-1] LOG: duration:
> 567.559 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='7537b74eab488de54d6e0167d1919207';
> Aug 25 14:53:32 forgehouse-s1 postgres[23722]: [2-1] LOG: duration:
> 565.966 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='d84613009a95296fb511c2cb051ad618';
> Aug 25 14:53:33 forgehouse-s1 postgres[23723]: [2-1] LOG: duration:
> 1192.789 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='d84613009a95296fb511c2cb051ad618';
> Aug 25 14:53:53 forgehouse-s1 postgres[23727]: [2-1] LOG: duration:
> 12159.162 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='d84613009a95296fb511c2cb051ad618';
> Aug 25 14:53:54 forgehouse-s1 postgres[23728]: [2-1] LOG: duration:
> 3283.185 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='7537b74eab488de54d6e0167d1919207';
> Aug 25 14:53:57 forgehouse-s1 postgres[23729]: [2-1] LOG: duration:
> 2116.516 ms statement: UPDATE session SET hit_time=now() WHERE
> md5='7537b74eab488de54d6e0167d1919207';
>
> Take a look to the timestamps... they are not really close to each other...

Eh? The timestamps show that the updates *are* close to each other.
What we don't know is whether this log excerpt shows all statements
that were executed during its time frame. It might have been grep'ed
from the full log file, or the log_min_duration_statement setting
might be such that only statements lasting more than a certain
amount of time are logged and we're not seeing similar updates that
happened quickly, nor when any of the updates were committed.

Marc, does my hypothesis of updates being blocked by other transactions
sound plausible in your environment? How complete a log did you
post -- is it everything, or are there other statements that you
omitted or that weren't logged because of the log_min_duration_statement
setting?

--
Michael Fuhr