Re: choosing the right platform - Mailing list pgsql-performance

From scott.marlowe
Subject Re: choosing the right platform
Date
Msg-id Pine.LNX.4.33.0304091152550.22442-100000@css120.ihs.com
Whole thread Raw
In response to Re: choosing the right platform  ("Matthew Nuzum" <cobalt@bearfruit.org>)
Responses Re: choosing the right platform
List pgsql-performance
On Wed, 9 Apr 2003, Matthew Nuzum wrote:

> I'm glad to hear your comments about Solaris, I'm really most comfortable
> with Linux and I think I can pick up BSD pretty easily.
>
> About the Intel platform though,
>
> It's only been pretty recently (relatively speaking) that servers based on
> IA32 architecture have had support for greater than 2GB of RAM.  I've heard
> talk about problems with applications that require more than 2GB.  I do
> believe that my tables will become larger than this, and the way I
> understand it, sort mem works best when the tables can be loaded completely
> in RAM.
>
> I don't suspect that individual tables will be 2GB, but that the size of all
> tables combined will be.  If there is a limitation on the largest chunk of
> RAM allocated to a program, will I have problems?

A couple more suggestions.  One is to never allocate more than 50% of your
memory to a database's shared buffers, i.e. let the OS buffer the disks en
masse, while the database should have a smaller buffer for the most recent
accesses.  This is because kernel caching is usually faster and more
efficient than the database doing it, and this becomes more an issue with
large chunks of memory, which both Linux and BSD are quite good at
caching, and postgresql, not so good.

The other is to look at Linux or BSD on 64 bit hardware (Sparc, IBM
Zseries mainframes, SGI Altix, etc...) where the one thing that's worth
being on the bleeding edge for is databases and their memory hungry ways.
:-)


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