Re: Upgrade to dual processor machine?

On 13 Nov 2002 at 8:29, Henrik Steffen wrote:

> Hello Josh!
>
> This is was I figured out now:
>
> 1) RAM available: 1024 MB, there's nothing else but postgres on this
>    machine, so if I calculate 128 MB for Linux, there are 896 MB left
>    for Postgres.
>
> 2) 70 % of 896 MB is 627 MB
>
> Now, if I follow your instructions:
>
> 250K +
> 8.2K * 128 (shared_buffers) = 1049,6K +
> 14.2K * 64 (max_connections) = 908,8K +
> 1024K * 5000 (average number of requests per minute) = 5120000K
> ===============================================================
> 5122208.4K ==> 5002.16 MB
>
> this is a little bit more than I have available, isn't it? :(((

Obviously tuning depends upon application and you have to set the threshold by
trial and error.

I would suggest following from some recent discussions on such topics.

1)Set shared buffers somewhere between 500-600MB. Tha'ts going to be optimal
range for a Gig of RAM.

2) How big you database is? How much of it you need it in memory at any given
time? You need to get these figures while setting shared buffers. But still 500-
600MB seems good because it does not include file system cache and buffers.

3) Sort mem is a tricky affair. AFAIU, it is used only when you create index or
sort results of a query. If do these things seldomly, you can set this very low
or default. For individual session that creates index, you can set the sort
memory accordingly. Certainly in your case, number of requests per minute are
high but if you are not creating any index/sorting in each query, you can leave
the default as it is..

HTH

Bye
 Shridhar

--
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