On 07/09/2012 05:20 PM, Yan Chunlu wrote:
the value of "log_min_messages" in postgresql.conf is error, I have
changed it to "warning", so far does not received any warning, still
waiting.
When trying to track down performance issues, increasing logging to at
least `info' would seem to be sensible.
I suggest increasing your logging and enabling the auto_explain module
so it logs slow queries. If you can afford the substantial performance
hit you could enable its analyze mode to get details on why.
beside I do see some COMMIT which is relatively slow for example:
60 2012-07-08 00:00:29 CST [19367]: [131-1] LOG: duration: 375.851
ms statement: COMMIT
61 2012-07-08 00:00:30 CST [19367]: [132-1] LOG: duration: 327.964
ms statement: COMMIT
That certainly is slow. Again, I suspect checkpoint activity could be at
fault. You may need to tune to spread your checkpoints out and use more
aggressive bgwriter settings. See the wiki for performance tuning info.
but only one "BEGIN" in the same one day log file, did that influence
the query time too?
Only one BEGIN in the whole day? Or do you mean "only one BEGIN slow
enough to trigger slow query logging" ?
Do you have a "log_min_duration_statement" directive set in your
postgresql.conf ?
--
Craig Ringer
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