Re: Scalability in postgres

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





2009/5/28 Scott Mead <scott.lists@xxxxxxxxxxxxxxxx>
On Thu, May 28, 2009 at 4:53 PM, Fabrix <fabrixio1@xxxxxxxxx> wrote:



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 :).

--Scott

 


[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux