Wow, that's some serious context-switching right there - 300k context switches a second mean that the processors are spending a lot of their time fighting for CPU time instead of doing any real work.
There is a bug in the quad core chips during a massive amount of connections that will cause all cores to go to 100% utilization and no work be done. I'm digging to find links, but if I remember correctly, the only way to fix it was to disable the 4th core in linux (involved some black magic in /proc). You really need to lower the number of processes you're forcing each processor bus to switch through (or switch to AMD's hyper-transport bus).
The server HP is already AMD proccesor. The server with 4 dual core had max_connections = 5000 too, but the maximum of connections at time were 1800 and work very well.
If you get the link on the bug's quad core I would greatly appreciate
It appears that you have the server configured with a very high number of connections as well? My first suggestion would be to look at a way to limit the number of active connections to the server at a time (pgPool or similar).
yes, i have max_connections = 5000 can lower, but at least i need 3500 connections
Typically, it's a bad idea to run run with anything over 1000 connections (many will suggest lower than that). If you need that many connections, you'll want to look at a connection pool like pgBouncer or pgPool.
Postgres does not support more than 1000? even the server is very robust? I will try to lower... and already i have a pool (not pgpool and not pgBouncer). I have distributed all connections in three servers :).
