"mark" <dvlhntr@gmail.com> writes:
> If you get to many persistent or otherwise idle connections you might be
> inducing a "thundering herd" condition. Seems like on our servers we hit a
> wall with just having a lot of persistent connections from various apps. I
> don't really understand everything involved here but....
> It seems that a high number of idle connections processes will sleep on the
> same semaphore. When this becomes run-able all the idle connections that
> were sleeping on it become run-able at the same time. This means hundreds
> (in our case) of idle processes do some work even though they are idle at
> the same time. This eats all available cpu time for a few seconds then
> everything goes back to sleep.
What you're describing sounds a lot like the known issue with sinval
queue overflow response ... but that was fixed in 8.4. What version
is this?
regards, tom lane