From: Harald Armin Massa <haraldarminmassa@gmail.com>
To: Magnus Hagander <mha@sollentuna.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: measuring shared memory usage on Windows
Date: Mon, 16 Oct 2006 13:18:40 +0200
Message-ID: <7be3f35d0610160418u51e4d256k15ee2a5e4ba9433@mail.gmail.com> (raw)
In-Reply-To: <6BCB9D8A16AC4241919521715F4D8BCEA357EE@algol.sollentuna.se>
References: <7be3f35d0610160215v21edbe48vc144200a83f41dd0@mail.gmail.com>
<6BCB9D8A16AC4241919521715F4D8BCEA357EE@algol.sollentuna.se>
Magnus,
> So: has anybody a hint how I can check how much shared_memory
> > is really used by PostgreSQL on Windows, to fine tune this parameter?
> >
> > I learned the hard way that just rising it can lead to a hard
> > performance loss :)
>
> Not really sure :) We're talking about anonymous mapped memory, and I
> don't think perfmon lets you look at that.
thanks for the clarification. However,
"anonymous mapped memory" site:microsoft.com
turns out 0 (zero) results. And even splitting it up there seems to be
nearly no information ... is the same thing by any chance also known by
different names?
> However, there is no limit to it as there often is on Unix - you can map
up to whatever the virtual RAM
> size is (2Gb/3Gb dependingo n what boot flag you use, IIRC). You can
> monitor it as a part of the total memory useage on the server, but
> there's no way to automatically show the difference between them.
So the "performance shock" with high shared memory gets obvious: memory
mapped files get swapped to disk. I assume that swapping is nearly
transparent for the application, leading to a nice trashing ...
I'll keep on searching...
Harald
--
GHUM Harald Massa
persuadere et programmare
Harald Armin Massa
Reinsburgstraße 202b
70197 Stuttgart
0173/9409607
-
Python: the only language with more web frameworks than keywords.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: haraldarminmassa@gmail.com, mha@sollentuna.net
Subject: Re: measuring shared memory usage on Windows
In-Reply-To: <7be3f35d0610160418u51e4d256k15ee2a5e4ba9433@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox