Re: shared_buffer advice

AI Rumman wrote:
> I have a server with Dual-Core 4 cpu and 32 GB RAM.
> This is the database server. Only Postgresql 8.1 is running on it with
> multiple databases.
> How should I plan for shared_buffers and effective cache size?

Set shared_buffers very low--at most 128MB--because you're running
PostgreSQL 8.1.  If you upgrade to 8.3 or later, which you should, you
might explore higher values.  On 8.1 and 8.2, trying to use any large
size for shared_buffers makes the whole database freeze under any sort
of heavy write load when checkpoints happen.

The first question you should be asking is not "how can I tune the
parameters on my 8.1 server?", it should be "how can I upgrade this 8.1
server to a newer version?".  That's not always possible, because some
8.1 applications won't run on 8.3 or later without changes to them.  But
moving onto 8.3 is by far a better way to get better performance from
your system than trying to tune 8.1.

--
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us