mkscott@sacadia.com

From lamar.owen@wgcr.org Thu Jun 28 11:14:10 2001

Return-path: <lamar.owen@wgcr.org>

Received: from www.wgcr.org (IDENT:root@www.wgcr.org [206.74.232.194])

by candle.pha.pa.us (8.10.1/8.10.1) with ESMTP id f5SFE9U18758

for <pgman@candle.pha.pa.us>; Thu, 28 Jun 2001 11:14:09 -0400 (EDT)

Received: from lowen.wgcr.org (IDENT:lowen@[10.1.2.3])

by www.wgcr.org (8.9.3/8.9.3/WGCR) with SMTP id LAA11879;

Thu, 28 Jun 2001 11:14:14 -0400

Content-Type: text/plain;

charset="iso-8859-1"

From: Lamar Owen <lamar.owen@wgcr.org>

To: Bruce Momjian <pgman@candle.pha.pa.us>

Subject: Process weight (was:Re: [GENERAL] Re: Red Hat to support PostgreSQL)

Date: Thu, 28 Jun 2001 11:14:09 -0400

X-Mailer: KMail [version 1.2]

References: <200106272258.f5RMwIb26959@candle.pha.pa.us>

In-Reply-To: <200106272258.f5RMwIb26959@candle.pha.pa.us>

MIME-Version: 1.0

Message-ID: <01062811140902.01118@lowen.wgcr.org>

Content-Transfer-Encoding: 8bit

Status: ORr

On Wednesday 27 June 2001 18:58, Bruce Momjian wrote:

> > I had almost given up on using Postgres for this system because under

> > Solaris, it just couldn't cut it (MySQL could do the work with one CPU

> > while Postgres took up even more CPU and required *both* CPUs to be

> > enabled), but when we moved the system to a Linux box, things worked

> > much better.

> Ah, back to a PostgreSQL topic. :-)

> My guess on this one is that Solaris is slower for PostgreSQL because

> process switching is _much_ heavier on Solaris than other OS's. This is

> because of the way they implemented processes in SVr4. They got quite

> heavy, almost requiring kernel threads so you weren't switching

> processes all the time.

Now, the question of the week:

Is supporting a thread model for an inefficient OS a desirable thing to do,

when more efficient OS kernels are available such as FreeBSD 4.x and Linux

2.4? My opinion is that our existing model, when used with a

connection-pooling frontend, is rather efficient. (Yes, I use a

connection-pooling frontend. Performance is rather nice, and I don't have to

have a full backend spawned for every page hit.)

In fact, on a Linux box threads show as processes. While I know that the

kernel actually supports themin a slightly different manner than processes,

they have more similarities than differences.

However, even on OS's where threads are supported, the mechanism to support

those threads must be an efficient one -- not all pthreads libraries are

created equal. Many are frontends (expensive ones, at that) for plain old

processes.

Does anyone know of a resource that details the 'weight' of processes for our

supported platforms? [reply off-list -- I'll be glad to summarize responses

to HACKERS, ADMIN, or PORTS, as appropriate, if desired.]

--

Lamar Owen

WGCR Internet Radio

1 Peter 4:11