Re: The never ending quest for clarity on shared_buffers - Mailing list pgsql-performance

From Paul Ramsey
Subject Re: The never ending quest for clarity on shared_buffers
Date
Msg-id 41647127.3060407@refractions.net
Whole thread Raw
In response to The never ending quest for clarity on shared_buffers  (Doug Y <dylists@ptd.net>)
Responses Re: The never ending quest for clarity on shared_buffers  (Neil Conway <neilc@samurai.com>)
List pgsql-performance
Doug Y wrote:

>   For idle persistent connections, do each of them allocate the memory
> specified by this setting (shared_buffers * 8k), or is it one pool used
> by all the connection (which seems the logical conclusion based on the
> name SHARED_buffers)? Personally I'm more inclined to think the latter
> choice, but I've seen references that alluded to both cases, but never a
> definitive answer.

The shared_buffers are shared (go figure) :).  It is all one pool shared
by all connections.  The sort_mem and vacuum_mem are *per*connection*
however, so when allocating that size you have to take into account your
expected number of concurrent connections.

Paul

pgsql-performance by date:

Previous
From: Gabriele Bartolini
Date:
Subject: Data warehousing requirements
Next
From: Gaetano Mendola
Date:
Subject: Re: Excessive context switching on SMP Xeons