Re: Postgres eats all memory

Hi all,

thank you very much for your quick response and your support.

It seems we found the culprit. The shown memory consumption (top, free
-m)
was a false trace. As Bill said it is not a bad thing that the systems
uses
the available memory...

The culprit in this case slowing down Postgres was the hard drive
itself.
The performance of the sata-disks (raid) was very bad. We replaced them
with
sas-disks (raid) and now everything runs as fast as expected.

Greetings
Eric Bartels

-----Original Message-----
From: Bill Moran [mailto:wmoran(at)collaborativefusion(dot)com]
Sent: Wednesday, August 13, 2008 2:44 PM
To: Bartels, Eric
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Postgres eats all memory

In response to "Bartels, Eric" <e(dot)bartels(at)customsoft(dot)de>:

> Hi there,
>
> we are running a fresh Postgres 8.3 installation with a single
> database with about 80GB of data.
>
> After a while the whole system memory is eaten up and every
> operation becomes very slow. Shortly after a system reboot
> and even without sending queries against the database the
> whole system memory is consumed after some time.
>
> Are there any settings that need to be set to avoid this?
> Currently the default settings are used ...
>
> The system is a Suse Enterprise Linux (64bit).

Provide some snapshots of the top command.

Default settings for PostgreSQL will not use all system memory, they're
actually too memory conservative for most use.

You're missing a TON of details here. I recommend you tell the list
how _much_ memory your system as, in additional to providing your
postgresql.conf file and a top snapshot demonstrating the problem.

My suspicion is one or more of the following:
1) You don't have very much RAM in your system and you're overloading
it with connections or otherwise
2) You're running things other than PG on this system that are eating
RAM.
3) You're being fooled by the fact that Linux will use all the available
RAM all the time (which isn't particularly a bad thing)

--
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran(at)collaborativefusion(dot)com
Phone: 412-422-3463x4023