Re: Shared Memory Sizing

On Thu, Jun 27, 2002 at 01:44:56PM -0700, Glen Parker wrote:

> Obviously a lot of people disagree with this...  I'd like to understand
> why this approach is considered incorrect when postgres rather owns the
> machine?

If you starve other things on the machine for memory, you'll cause
swapping.

Consider all the other things you're doing on the machine -- just
little things, like cron and such.  All that takes memory.
Therefore, it's dangerous not to let the OS manage a good chunk of
memory.

There also appears to be a diminishing returns problem: at a certain
point, you're unlikely to need more shared space, and if you do
something else on the machine that could use the memory, you're
throwing it away.  But I don't see that you're wrong in principle.
Just don't get it wrong -- I _have_ caused a 16 gig machine to swap.
It's not fun.

A

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