[Zope-dev] SWAP issue

Ahsan Imam Ahsan.Imam@newtimes.com
Thu, 05 Sep 2002 10:34:27 -0700


The kernel is  2.4.7-10.
Zope 2.5 on Red Hat 7.2
python 2.1.3

Here is what I think the problem is:
Some object or code was introduced on Tuesday morning.=20
The users are beginners so they could have introduced a never ending loop =
or something of that sort. I turned on profiling to see if thre was =
anything in particular consuming a lot of time. A the top of the list was =
Connection.py.=20

Is there a way catch that non terminating loop? This non-terminating loop =
is just a theory I have. I could be completely wrong. Are there other =
things I could look at for clues.


>>> Toby Dickenson <tdickenson@geminidataloggers.com> 09/05/02 06:46 AM =
>>>
On Thursday 05 Sep 2002 2:58 am, Ahsan Imam wrote:
> Hello All,
>
> I am currently running zope 2.5 and python 2.1.3.=20

Are you actually seeing the zope processes use too much memory?

2.5.x have a ZODB cache mechanism that does not respond well to memory=20
pressure. If your application touches many objects per transaction then=20
memory usage may grow out of control. 2.6 improves this significantly.

> The machine has 2 gigs of
> rams and is running on Red Hat 7.2.

Which kernel?

> After starting zope eveything works fine for a while. Slowly the swap
> starts to swell up

Memory that is not being actively used might as well be moved into =
swap,=20
freeing the ram for more productive uses. This does not necessarily =
indicate=20
a problem.

> and after a few hours the machine has to be rebooted.
> The funny thing is that free shows that there is almost a gig of RAM =
free
> and swap keeps on growing.=20

Are you sure you are interpreting the output from 'free' correctly? It =
is=20
often misinterpreted. (please post the output from 'free -m' if you are =
not=20
sure.)

> After a while the machine simply hangs.

> I have recompiled python and zope. Turned on profiling.
> I have looked through the stupid.log. There are no core dumps either. I
> have also tried running zope with one thread.
>
> Does anyone have suggestions.

you havent explained why you think this is a zope problem.