Re: Starting PostgreSQL 8.0.4 with more memory [FreeBSD

On Mon, 2005-10-31 at 14:48 -0800, Chris Travers wrote:
> Simon Riggs wrote:

> >Your point was about cache efficiency as an argument for not increasing
> >shared_buffers. Politely, I don't accept that argument. Clearly, there
> >are some other considerations (for which I agree completely) but those
> >don't prevent you increasing shared_buffers, they just place limits on
> >your overall memory budget which could effect shared_buffers of course.
> >

> I can see some circumstances where it might make some sense to have high
> shared buffer arrangements.
>
> However, I think that Tom and others are speaking to typical cases, and
> I think you seem to be speaking to the case where you have a database
> where you have many reads and only a few writes, and where a few tables
> are far more often used that the rest.  So it strikes me as an argument
> against making such the general recommendation.  Of course, if your
> database benefits from turning off bgwriter and increasing shared
> buffers, you might find that useful.  Just be aware that it is likely to
> be applicable only to a small subset of the PostgreSQL deployments.

This all depends upon what you see as typical. I see more than one
"typical" deployment - I see three, maybe more:

- OLTP/ Current State data management
- Data Warehouse
- Log Archiver

Each are fairly different in many respects, so I see few "general
recommendations" that really do apply to everybody. So thats why I
didn't attempt to make a general recommendation myself, just pointing
out that you can if you want and there's nothing physically stopping you
from putting shared_buffers high (in 8.1).

Best Regards, Simon Riggs