Re: How to find how much postgresql use the memory?

Ok I see. So what's the best way to find optimum value for various
memory-related setting of postgresql ?

On Tue, Jan 20, 2009 at 3:27 PM, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>wrote:

> > I wonder how to find how much postgresql memory consumption
> > is (real, not allocated) ?
>
> You could install the pg_buffercache contrib and
>
> SELECT pg_size_pretty(
> CAST(current_setting('block_size') AS integer) * max(bufferid)
> )
> FROM pg_buffercache WHERE relfilenode IS NOT NULL;
>
> to find out how much of the shared memory in the buffer pool is
> actually in use.
>
> There is some extra shared memory that is used for other purposes,
> and there is private memory of the backends (the latter could be
> a significant number).
>
> Why do you want that number?
> If it is for tuning of shared_buffers, that is probably a bad way.
> Even if shared_buffers is set much higher than you'd actually need
> it, sooner or later all of your shared_buffers will be used, unless
> your database is tiny.
>
> Yours,
> Laurenz Albe
>