Thank you for the informative post.
We believe this was caused by a network issue yesterday after checking our network speeds. We were maxing our ethernet port at 100 mbps, i believe some apache processes were hanging because of this issue, having no available bandwidth left. Considering an upgrade to a gbps port and we will see how this will effect.
On Tue, Oct 6, 2009 at 9:28 AM, Steve Crawford
<scrawford@pinpointresearch.com> wrote:
Aras Angelo wrote:
...
When i kill the earliest idle process the others stop too. So i dont know whats wrong really. All our apps use the same footer, with pg_close() at the end....
...
I have done most of the things you guys suggested, so it seems to me that something between php-apache-postgresql is not doing good, and it only effects us at peak times, so just wondering if killing processes every 2-3 minutes, would do harm on our setup....
Are you killing web processes or postgresql processes? If web, you will probably end up impacting at least some of you users directly. If PostgreSQL, then you will undoubtedly end up yanking the rug out from under a process that expected a working database connection. So yes, you might cause harm. Worse still, you may not solve the problem.
When I hear symptoms like this, especially when they tend to happen under load, I start looking for a process that is slowing/blocking the other processes.
Consider a fairly typical PHP script. It might start out opening a database connection and then do various queries interspersed with processing. If one process hogs sufficient resources or is holding some resource or lock that slows or blocks the other PHP processes then you could easily see numerous idle PG processes. Kill the "offending" process and the others will often rapidly complete thus releasing their connections.
If you have enough traffic to justify three webservers then you probably have enough traffic to deplete your available pg connections in seconds, not minutes so keep digging.
Cheers,
Steve