Re: Same stament sometime fast, something slow

Kevin Grittner wrote:
> Two common causes for this are blocking and overloading the I/O
> system at checkpoint.  You might want to turn on logging of
> checkpoints to see if this happens only during checkpoints.  See this
> page for techniques to look at blocking:
>
> http://wiki.postgresql.org/wiki/Lock_Monitoring
>

I just updated this to mention use of log_lock_waits to help here.
Looking for patterns in log_min_duration_statement, log_checkpoints, and
log_lock_waits entries, seeing which tend to happen at the same time, is
the usual helpful trio to investigate when having intermittent slow
queries.  Of course, with Windows running on a VM, there's a hundred
other things that could be causing this completely unrelated to the
database.

--
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services and Support        www.2ndQuadrant.us
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