Re: Docs about buffers and sortmem setting

On Thu, Nov 14, 2002 at 10:43:44AM +0100, Ryszard Lach wrote:
> Hi!
>
> I've seen on this list some calculations concerning buffers and sort_mem
> settings. Could you tell me if there is a document about such a
> calculation? I'd like to use nearly all of my RAM for postgres.

Probably that's not true.  You'll likely cause swapping if you try
to.

The general rule of thumb is to try about 25% of physical memory for
your buffer size.  Some people like to increase from there, until
swapping starts, and then back off; but there are arguments against
doing this, given the efficiency of modern filesystem buffering.

In practice, a buffer size in the tens of thousands is probably
adequate.  We actually have discovered long-term negative performance
effects if the buffers are set too large.

A

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