On 06/25/2012 11:00 PM, Radovan Jablonovsky wrote:
Thanks for response,
How were the connections refused (error message)?
2012-06-13 13:45:38.809 MDT [25172]: [1-1] FATAL: remaining connection slots are reserved for non-replication superuser connections
2012-06-13 13:45:38.889 MDT [25173]: [1-1] FATAL: remaining connection slots are reserved for non-replication superuser connections
2012-06-13 13:45:38.895 MDT [25174]: [1-1] FATAL: remaining connection slots are reserved for non-replication superuser connections
Could it be that there are already max_connections sessions? max_connection was set to 600, when issue occurred the db server had 85 connection and server was under medium load.
I can't explain why it was topping out at 85 when it was set to 600, but - I strongly recommend that you switch to a connection pool and lower your max_connections considerably. You'll likely get much better performance with max connections at 20 or less - the usual rule of thumb is "num_hdds + num_cpus" but in reality you need to benchmark and tune to work out what's best.
pgbouncer is a good light-weight pooling option.
--
Craig Ringer