Обсуждение: Max connections

On Tue, Aug 11, 2009 at 3:42 PM, Benjamin Krajmalnik <kraj@illumen.com> wrote:

Increasing max_connection will make PostgreSQL to request more System V shared memory or semaphores than your operating system's default configuration allow. Did you tune/tweak the kernel options for that? Details for those options can be found at

http://www.postgresql.org/docs/8.3/static/kernel-resources.html#SYSVIPC

--
Shoaib Mir
http://shoaibmir.wordpress.com/

"Benjamin Krajmalnik" <kraj@illumen.com> writes:
> I am setting up a test environment to simulate a very high load.  We
> have a server farm which is receiving data (cold be thousands of
> simultaneous users posting data).  I currently have max_connections set
> to 500 and the server is starting ok.  If I try to increase the
> max_connections to 1000, the server is unable to start.  I am running a
> VM with 4GB RAM.  Swap space is not being used, and the system is
> showing about 1.5GB of ram not being utilized.

Quite honestly, you're living in fantasy land if you expect to support
1000 concurrently active backends on such a restricted server.  Get
yourself a connection pooler and knock down max_connections to 100 or
so.

            regards, tom lane

Tom,

This exercise is exactly to help us size our production server, but I
appreciate what you are saying.
I am using pgbouncer, but my understanding is that I need to make as
many potential connections available on the server side as the maximum
pool size - I will shoot them an email to get some guidance.

As always, thank you so much for your assistance.


> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Tuesday, August 11, 2009 7:54 AM
> To: Benjamin Krajmalnik
> Cc: pgsql-admin@postgresql.org
> Subject: Re: [ADMIN] Max connections
>
> "Benjamin Krajmalnik" <kraj@illumen.com> writes:
> > I am setting up a test environment to simulate a very high load.  We
> > have a server farm which is receiving data (cold be thousands of
> > simultaneous users posting data).  I currently have max_connections
> set
> > to 500 and the server is starting ok.  If I try to increase the
> > max_connections to 1000, the server is unable to start.  I am
running
> a
> > VM with 4GB RAM.  Swap space is not being used, and the system is
> > showing about 1.5GB of ram not being utilized.
>
> Quite honestly, you're living in fantasy land if you expect to support
> 1000 concurrently active backends on such a restricted server.  Get
> yourself a connection pooler and knock down max_connections to 100 or
> so.
>
>             regards, tom lane