[Zope] Memory Leak Debugging

Jonathan Bowlas me at jonbowlas.com
Tue Feb 28 08:20:40 EST 2006

Hi All,

A few weeks ago I posted this message to the list but we still haven't
resolved our memory leak, mainly because we have no idea where to look.

So having trawled around a few forums I decided to install the LeakFinder
product onto our development server and click around a little watching the
refcounts. Here I noticed that Products.Silva.Image.Image &
DateTime.DateTime.DateTime had the largest number of references. So
following the LeakFinder instructions I attempted to patch each of these

I started with the Products.Silva.Image.Image class and continued to click
around to return some results, unfortunately this never returned any results
at all so that wasn't much help. Next I patched the
DateTime.DateTime.DateTime class which returned a huge amount of information
on the results tab. So I'm now hoping someone could help me in deciphering
these results and explain what exactly should I be looking for here? And it
would also be useful to know why the Products.Sivla.Image.Image class
doesn't return any results at all.

Hope someone can help.


-----Original Message-----
From: zope-bounces at zope.org [mailto:zope-bounces at zope.org] On Behalf Of
Jonathan Bowlas
Sent: 15 February 2006 11:49
To: zope at zope.org
Subject: RE: [Zope] Memory Leak Debugging

Hi All,

We're having serious problems with performance running Silva CMS on Zope
2.7.8-final, python 2.3.5, linux2 set up on a machine with 2.5GB RAM. There
are currently only about 65 users and around 2000 documents in the CMS but
it seems to run for a week, then the RAM fills up and crashes so we have to
restart the server manually.

The Zope logs aren't much help as I enquired on the Zope list and their
response was we need more RAM. But surely 2.5GB is enough.

I've also checked Control_Panel/DebugInfo for any refcounts with significant
jumps and Products.Silva.Image.Image seems to be the culprit:
                                       11.32am  11.36am
Products.Silva.Image.Image             56203    58153          +1950
Acquisition.ImplicitAcquirerWrapper    44825    45151          +326

So we've tried to figure out which kind of request triggers these refcount
jumps by creating a separate instance with a very small ZODB Cache (so it
gets filled up soon), and clicked around a little, watching the refcounts
but we cannot seem to replicate it.

So basically this is a plea for help from an expert Zope debugger who can
assist us in finding the source of the problem so we can resolve it. Or
alternatively someone who can give us a set of instructions that we can
follow that will enable us to locate the problem, I've googled it and there
are no clear answers.

FYI we have the following products installed on our Zope instance.

Annotations 0.4.3
DocFinderTab (0.5.2)
External Method-1-0-0
FileSystemSite 1.4.2
Formulator 1.10
Groups 0.4
IssueTrackerProduct (0.6.13)
LDAPUserFolder (2.3)
ParsedXML 1.4
PlacelessTranslationService (1.0)
ProxyIndex 1.2
Silva 1.4.1
SilvaBlog 0.4.2
SilvaCustomAutoTOC 0.9
SilvaDocument 1.4.1
SilvaDocumentPatches 1.3b6-1
SilvaExtETHLDAP 0.7
SilvaExternalSources 0.10.3
SilvaMetadata 0.10
SilvaNewsNetwork 2.0
SilvaReferenceChecker 0.2
SilvaStylesheets 0.6.2
SilvaUCLAttributes 0.7 - (A UCL product*)
Silva UCL Gallery 0.1 - (A UCL product*)
SilvaUCLSubjectAudienceFilters 0.6 - (A UCL product*)
SilvaViews 0.11
SiteErrorLog Sprout 0.6.2
Tropos (1.9.12)
XMLWidgets-Pluggable 0.13 (CVS/UNRELEASED)
ZMySQLDA 2.0.8
ZReST (1.1)
Zope Tutorial 1.2
kupu 1.3.2 
z3locales 0.1

If you require any further information do not hesitate to ask.

Hope someone can help.

Jon Bowlas
University College London

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