Re: Queries sometimes take 1000 times the normal time

"Anders K. Pedersen" <akp@cohaesio.com> writes:
> Currently there's only a few users in the database for testing purposes,
> and most of the time the user lookup's take 2-3 ms (I have syslog'ing of
> queries and duration turned on), but several times per hour the duration
> for one of the queries is 2-3 seconds (1000 times larger), while the
> surrounding lookups take the usual 2-3 ms.

One thing that comes to mind is that the slow query could be occurring
at the same time as a checkpoint, or some other cycle-chewing background
operation.  It's not clear why a checkpoint would slow things down that
much, though.  Anyway I'd suggest looking for such activities; once we
know if that's the issue or not, we can make some progress.

            regards, tom lane