Re: how much memory to allot to postgres?

On 29 Jan 2003 at 13:34, Francisco J Reyes wrote:

> On Tue, 28 Jan 2003, Shridhar Daithankar wrote:
>
> > 15000 shared buffers + 10Mb of WAL cache + 4MB of sort mem(Note this is per
> > client) should be enough to handle enough data.
>
> Just checked my values and I have 128MB for vacuum and sort. Is that
> overkill?

Absolutely. Especially sort mem. If you are allocatingg 128MB sort mem for each
connection, you will soon be dry with memory. I would say 8MB to 16MB sort
memory depending upon number of conenctions you want to entertain at a time.
Just remember it is per connection.

Vacuum memory need not be that high. 32MB is like good enough. For vacuum to be
very fast and effective, you also need to up the fsm relation pages. Tom has
said that already.

> 2GB ram also, but usually only have a handfull of connections.
> Given that WAL buffer is listed in 8K block (correct?) then 10MB would be
> 1310720?

<Puzzled> How did you calculate that? If I am right, 10MB should be something
like 1280 buffers isn't it? 14K buffers are 117MB or so, last I remember.

Just recheck the calculation..

> It seems I only have 2MB of WAL buffer.. I have large daily loads of data.
> Will a number above 10MB help? ie 16MB

16MB is good.

Most important point is rule of thumb does not serve you anyway. You have to
test run and hand tune your database. These are just experiences of other
people which might help you.

HTH

Bye
Shridhar

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