Re: Setting Shared Buffers , Effective Cache, Sort Mem Parameters

On Thu, 22 Apr 2004 13:51:42 -0400, Pallav Kalva <pkalva(at)deg(dot)cc> wrote:
>I need some help with setting these parameters (shared buffers,
>effective cache, sort mem) in the pg_conf file.

It really depends on the kind of queries you intend to run, the number
of concurrent active connections, the size of the working set (active
part of the database), what else is running on the machine, and and and
...

Setting shared_buffers to 10000, effective_cache_size to 400000 (80% of
installed RAM), and sort_mem to a few thousand might be a good start.

> Also can anyone explain
>the difference between shared buffers and effective cache , how these
>are allocated in the main memory (the docs are not clear on this).

Shared_buffers directly controls how many pages are allocated as
internal cache. Effective_cache_size doesn't allocate anything, it is
just a hint to the planner how much cache is available on the system
level.

Servus
Manfred