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Re: Help me put 2 Gigs of RAM to use

From: Mark Stosberg <mark(at)summersault(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Help me put 2 Gigs of RAM to use
Date: 2009-12-10 16:44:32
Message-ID: 20091210114432.4da95fb1@summersault.com (view raw or flat)
Thread:
Lists: pgsql-performance
Thanks for the response, Matthew.

> On Thu, 10 Dec 2009, Mark Stosberg wrote:
> > What I'm noticing is that the while the FreeBSD server has 4 Gigs of
> > memory, there are rarely every more than 2 in use-- the memory use
> > graphs as being rather constant. My goal is to make good use of those 2
> > Gigs of memory to improve performance and reduce the CPU usage.
> 
> I think you'll find that the RAM is already being used quite effectively 
> as disc cache by the OS. It sounds like the server is actually set up 
> pretty well. You may get slightly better performance by tweaking a thing 
> here or there, but the server needs some OS disc cache to perform well.

As part of reviewing this status, I it appears that the OS is only
addresses 3 of the 4 Gigs of memory. We'll work on our FreeBSD setup to
cure that.

Here's how "top" reports the memory breakdown:

Mem: 513M Active, 2246M Inact, 249M Wired, 163M Cache, 112M Buf, 7176K
Free Swap: 9216M Total, 1052K Used, 9215M Free

So perhaps the OS disc cache is represented in the "Inactive" memory
statistic? I suppose once we have the 4th Gig of memory actually
available, that would all be doing to the disk cache. 

> > (We currently run 8.2, but are planning an upgrade to 8.4 "soon").
> 
> Highly recommended.

For performance improvements in particular?

    Mark

-- 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . 
   Mark Stosberg            Principal Developer  
   mark(at)summersault(dot)com     Summersault, LLC     
   765-939-9301 ext 202     database driven websites
 . . . . . http://www.summersault.com/ . . . . . . . .



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