Re: Caching (was Re: choosing the right platform) - Mailing list pgsql-performance

From Josh Berkus
Subject Re: Caching (was Re: choosing the right platform)
Date
Msg-id 200304092045.29503.josh@agliodbs.com
Whole thread Raw
In response to Caching (was Re: choosing the right platform)  ("Matthew Nuzum" <cobalt@bearfruit.org>)
Responses Re: Caching (was Re: choosing the right platform)
List pgsql-performance
Matthew,

> ** Postgres is multi-process, not multi-threaded (?)

Correct.

> ** It's better to not use huge amount of sort-mem but instead let the OS do
> the caching (?)

That's "don't use a huge amount of *shared_buffers*".  Sort_mem is a different
setting.  However, I have never seen a database use more than 32mb sort mem
in a single process, so I don't think the 2GB limit will hurt you much ...

> ** My needs are really not going to be as big as I think they are if I
> manage the application/environment correctly (?)

Your needs *per process*.   Also, PostgreSQL is not as much of a consumer of
RAM as it is a consumer of disk I/O.

> * FreeBSD is going to provide a better file system than Linux (because
> Linux only supports large files on journaling filesystems which impose
> extra over head) (this gleaned from this conversation and previous threads
> in archives)

No, the jury is still out on this one.   ReiserFS is optimized for small
files, and I've done well with it although some posters report stability
problems, though all second-hand.   We hope to test this sometime in the
upcoming months.

--
Josh Berkus
Aglio Database Solutions
San Francisco


pgsql-performance by date:

Previous
From: Josh Berkus
Date:
Subject: Re: Help analyzing 7.2.4 EXPLAIN
Next
From: Ron Johnson
Date:
Subject: Re: Caching (was Re: choosing the right platform)