From: Greg Smith <gsmith@gregsmith.com>
To: Andrew Sullivan <ajs@commandprompt.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Which hardware ?
Date: Tue, 17 Jun 2008 12:32:10 -0400 (EDT)
Message-ID: <Pine.GSO.4.64.0806171219410.10502@westnet.com> (raw)
In-Reply-To: <20080617154215.GI68434@commandprompt.com>
References: <g38epm$2pl4$1@news.hub.org>
<20080617142501.GG68434@commandprompt.com>
<g38ite$26gp$1@news.hub.org>
<20080617154215.GI68434@commandprompt.com>
On Tue, 17 Jun 2008, Andrew Sullivan wrote:
> A running JVM is necessarily going to use some memory, and that is
> memory use that you won't be able to factor out properly when developing
> models of your database system performance.
Now you've wandered into pure FUD. Tuning maximum memory usage on a Java
app so you can model it is straightforward (albeit a little confusing at
first), and in most cases you can just sample it periodically to get a
good enough estimate for database tuning purposes. JVMs let you adjust
maximum memory use with -Xmx , and if anything the bigger problem I run
into is that using too much memory hits that limit and crashes Java long
before it becomes a hazard to the database.
This is a system with 8GB of RAM here; having some Tomcat instances
co-existing with the database when there's that much room to work is not
that hard.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
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To: pgsql-performance@postgresql.org
Cc: gsmith@gregsmith.com, ajs@commandprompt.com
Subject: Re: Which hardware ?
In-Reply-To: <Pine.GSO.4.64.0806171219410.10502@westnet.com>
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