On Wednesday, November 9, 2011, Gauthier, Dave wrote:
Hi:
PG v4.8.3 on Linux
I'm using "selcet procpid,current_query from pg_stat_activity" to monitor activity during times when "top" is showing many PG procs with very high cpu usage numbers (all cores at or above 90%). Some of these are procs that map to PG connections with current_query = <IDLE>.
What scenarios could explain a process identified as IDLE consuming lots of CPU?
More clues... In parallel with these was a user that was making a series of insert/delete/update commands that fire off triggers that generate more DML recursively. Some of the idles are "<IDLE> in transaction".
My guess would be something running lots and lots of really short queries. top will give you an averate CPU usage over an interval, but pg_stat_activity shows a snapshot. So probably the sessions were running simple things, but just at the moment pg_stat_activity "hits", it wasn't doing anything.
--
Magnus Hagander
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http://www.hagander.net/ Work:
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