RE: [Zope-dev] Re: Preliminary findings: Zope 2.7 leakage caused by errors
Juan David, I'm using 1.0.1 ... I'm just abotu to try and test with 1.1.0a3 ... BTW, does that mean it's alpha software or something? is 1.1.0 stable? If the problem comes from Localizer I suspect this patch might be the cause: def new_publish(request, module_name, after_list, debug=0): id = get_ident() print "Localizer got thread id: " + str(id) Publish._requests[id] = request print "Request dict is now: " + str(Publish._requests) x = Publish.old_publish(request, module_name, after_list, debug) try: del Publish._requests[id] except KeyError: # XXX # Some people has reported that sometimes a KeyError exception is # raised in the previous line, I haven't been able to reproduce it. # This try/except clause seems to work. I'd prefer to understand # what is happening. LOG('Localizer', PROBLEM, "The thread number %s don't has a request object associated." % id) except: print "Localizer got an exception" return x What happens if an exception occurs here: x = Publish.old_publish(request, module_name, after_list, debug) ?? If some clean up code is supposed to occur it might be held back by the fact that there's a reference to the request kept in the global dictionary ... At least that's my theory :) But then I'm mostly uneducated about the intricacies of exception handling at this level, though I've been forced to learn quickly :) I'd be curious to know at least if you can reproduce the leak by generating loads of errors on a Localizer enabled site? One option would also be to simply wrap it in a try:catch and see what happens there ... But I noticed 1.1.0a3 uses a different model for wrapping the request, so that just might do the trick. Thanks for a very cool and useful product BTW. This is combination with the TranslationService is saving me loads of time. Cheers, J.F. -----Original Message----- From: zope-dev-bounces@zope.org [mailto:zope-dev-bounces@zope.org]On Behalf Of "J. David Ibáñez" Sent: May 20, 2004 6:47 AM To: Tres Seaver Cc: Jean-Francois.Doyon@ccrs.nrcan.gc.ca; brian@zope.com; chrism@plope.com; zope-dev@zope.org Subject: [Zope-dev] Re: Preliminary findings: Zope 2.7 leakage caused by errors Localizer (1.0.1) dynamically patches Zope, it stores a dictionary in the module "ZPublisher.Publish". The keys are integers, they are the values returned by Python's "thread.get_ident". The values are "ZPublisher.HTTPRequest.HTTPRequest" instances, they are not acquisition wrappers. Jean-François, which Localizer version do you use? Just to be sure we look at the same code. Tres Seaver wrote:
Jean-Francois.Doyon@CCRS.NRCan.gc.ca wrote:
Gents,
In following to the discussions regarding the leakage zope.org and my site suffer from, I've done some testing, and here's what I've found.
First of all, the leak does seem to occur when errors occur. Unlike what Chris suggested, I still suffer from this leak even when I completely remove standard_error_message.
How I tested:
I use JMeter, and a 99% identical box, dedicated for testing:
- RH 7.3 - Python 2.3.3 compiled with ./configure and no options - Zope 2.7 + a variety of products, both custom and well known (CMF, Localizer, etc ...)
I look at my error log on my main site to see the types of errors coming up and note the URL/parameters. Such errors include KeyErrors, a RecursionDepth error, a Method-something-or-other error, and so on.
I setup JMeter with multiple concurrent threads and run it. Within minutes I can see refcounts growing abnormally on the test server.
I then shut everything down and minimize the caches. The following are left around that shouldn't be:
Class May 19, 2004 1:52 pm May 19, 2004 2:26 pm Delta Acquisition.ImplicitAcquirerWrapper 1025 1309 +284 ZServer.HTTPResponse.ZServerHTTPResponse 150 247 +97 ZPublisher.BaseRequest.RequestContainer 146 240 +94 ZPublisher.HTTPRequest.HTTPRequest 172 262 +90
Right now I've focused on finding out why the Requests are still around.
Using the gc module, I've found that all leaked requests are being held by a dictionary. If I look at said dictionaries, this is what they might look like:
{'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/francais/mapsatoz>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/francais/mapsatoz>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>}, {3075: <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/maps/peopleandsociety/age/youth/HEAD>, 4100: <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/debug>, 5125: <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/debug>, 6150: <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/english/search/political>, 7175: <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/vh_
site/english/maps/archives/5thedition/other/referencemaps>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/debug>}, {'REQUEST': <HTTPRequest,
URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
_site/misc_/WFSAdapter/sqlmethod.gif>}
I know that the Localizer product does (or used to do) some kind of magic to make the REQUEST available to code as a "global". Can you reproduce this data without that product present?
NOTE: I had to hack the __repr__ of HTTPRequest not to use self['URL'] since it seems that attribute is unavailable in a closed request. I use PATH_INFO instead.
Most of the time I get the dictionary with the 'REQUEST' key. Those dictionaries with int's as keys are ones generated by the ExternalMethod I use to run the code to debug ... So even errors raised while trying to debug this leaks a dictionary that holds on to the request(s).
Said dictionary does not seem to be referred to by anything, at least not anything the gc module can find (gc.get_referrers()). One possible situation is that said dictionary is actually part of the HTTPRequest, and we have a cyclic reference problem. I don't think so however, I've looked at the HTTPRequest instances, and they have nothing in them other than strings, lists, basic dict's and an HTTPResponse instance. I'll take another look to be sure.
Again, I would be looking at the Localizer's module-level globals for this one.
Next step is too look at the Wrappers and see what they're all about and what's holding them there.
The wrappers are almost certainly there because the request is holding on to objects, which hold on to others, etc.
I'm hoping this information might give a clue to someone who knows Zope error handling better than I as to what might be the problem here ... Also I understand zope.org suffers from this? :)
Based on this information also, I have no reason to believe this is caused by product code ... I have to guess it's a Zope bug?
In some ways this is motivating me to reduce the number of errors that could occur, but because ALL errors seems to cause the problem, I ultimately have no control over it and under certain circumstances I suffer heavily from this. 404's alone probably cause this (I'm plannign to test that explicitely as well).
Thoughts, suggestions, comments welcome ...
I am CC'ing Juan-David, in case he may be able to offer any insights from the perspective of the Localizer product.
Tres.
-- J. David Ibáñez Founder and CTO of Itaapy <http://www.itaapy.com> 9 rue Darwin, 75018 Paris Tel +33 (0)1 42 23 67 45 / Fax +33 (0)1 53 28 27 88 _______________________________________________ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
The "a" in 1.1.0a3 means "alpha". If the problem is in Localizer 1.0.1 I think it will be in 1.1.0a3 too. Yes, I have a site with a similar behaviour, unfortunately today the network connection is too slooow, so I can't test that site. I'm going to do some local tests, though. Yes, the problem might be the fact that "new_publish" does not catch exceptions to remove the request from the dictionary. Jean-Francois.Doyon@CCRS.NRCan.gc.ca wrote:
Juan David,
I'm using 1.0.1 ... I'm just abotu to try and test with 1.1.0a3 ...
BTW, does that mean it's alpha software or something? is 1.1.0 stable?
If the problem comes from Localizer I suspect this patch might be the cause:
def new_publish(request, module_name, after_list, debug=0): id = get_ident() print "Localizer got thread id: " + str(id) Publish._requests[id] = request print "Request dict is now: " + str(Publish._requests) x = Publish.old_publish(request, module_name, after_list, debug) try: del Publish._requests[id] except KeyError: # XXX # Some people has reported that sometimes a KeyError exception is # raised in the previous line, I haven't been able to reproduce it. # This try/except clause seems to work. I'd prefer to understand # what is happening. LOG('Localizer', PROBLEM, "The thread number %s don't has a request object associated." % id) except: print "Localizer got an exception"
return x
What happens if an exception occurs here:
x = Publish.old_publish(request, module_name, after_list, debug)
??
If some clean up code is supposed to occur it might be held back by the fact that there's a reference to the request kept in the global dictionary ... At least that's my theory :) But then I'm mostly uneducated about the intricacies of exception handling at this level, though I've been forced to learn quickly :)
I'd be curious to know at least if you can reproduce the leak by generating loads of errors on a Localizer enabled site?
One option would also be to simply wrap it in a try:catch and see what happens there ... But I noticed 1.1.0a3 uses a different model for wrapping the request, so that just might do the trick.
Thanks for a very cool and useful product BTW. This is combination with the TranslationService is saving me loads of time.
Cheers, J.F.
-----Original Message----- From: zope-dev-bounces@zope.org [mailto:zope-dev-bounces@zope.org]On Behalf Of "J. David Ibáñez" Sent: May 20, 2004 6:47 AM To: Tres Seaver Cc: Jean-Francois.Doyon@ccrs.nrcan.gc.ca; brian@zope.com; chrism@plope.com; zope-dev@zope.org Subject: [Zope-dev] Re: Preliminary findings: Zope 2.7 leakage caused by errors
Localizer (1.0.1) dynamically patches Zope, it stores a dictionary in the module "ZPublisher.Publish". The keys are integers, they are the values returned by Python's "thread.get_ident". The values are "ZPublisher.HTTPRequest.HTTPRequest" instances, they are not acquisition wrappers.
Jean-François, which Localizer version do you use? Just to be sure we look at the same code.
-- J. David Ibáñez Founder and CTO of Itaapy <http://www.itaapy.com> 9 rue Darwin, 75018 Paris Tel +33 (0)1 42 23 67 45 / Fax +33 (0)1 53 28 27 88
Jean-Francois.Doyon@CCRS.NRCan.gc.ca wrote at 2004-5-20 09:58 -0400:
... def new_publish(request, module_name, after_list, debug=0): id = get_ident() print "Localizer got thread id: " + str(id) Publish._requests[id] = request print "Request dict is now: " + str(Publish._requests) x = Publish.old_publish(request, module_name, after_list, debug) try: del Publish._requests[id] except KeyError: ...
This code cannot leak requests in large numbers (though it may leak a few requests for some time). Reason: Zope does not normally create new threads. This implies that thread_ids are reused and thereby old requests flushed from the dict. -- Dieter
participants (3)
-
"J. David Ibáñez" -
Dieter Maurer -
Jean-Francois.Doyon＠CCRS.NRCan.gc.ca