On Jul 19, 2:07 pm, "Russell Keith-Magee" <[EMAIL PROTECTED]> wrote: > On 7/19/07, oggie rob <[EMAIL PROTECTED]> wrote: > > > Please, if you've seen the same issue or have any helpful ideas to try > > to stop the error, let me know. > > I think I've seen the same problem (or, at least, an analogous one). > Unfortunately, I can't provide much by way of helpful debug or > solution - the sysadmin that identified the problem for us isn't > around for me to ask him for more details. > > As I recall, the problem was mod_python. Older versions of mod_python > had some sort of issue with caching python instances. As a result, if > you deployed two different versions of Django, the version of Django > that was provided to a given request was determined by the thread that > served the request. If the first request served by a thread used the > old version of Django, that was the version that was used for all > subsequent requests on that thread, regardless of the version that was > required to satisfy the request.
For the record, the description which was given to you whereby "if the first request served by a thread used the old version of Django, that was the version that was used for all subsequent requests on that thread" is nonsense. There has never been a problem with mod_python which would have caused that sort of behaviour. > I believe we fixed the problem by updating mod_python, but I'm not > completely certain on that. Always a good idea regardless. Using mod_python 3.3.1 is high recommended. Where problems can come up with hosting multiple Django instances is not with mod_python or Django, but with third party C extension modules which haven't been written correctly so as to be used concurrently from multiple Python sub interpreters. One concrete example which was identified recently was Decimal support in pyscopg module. http://www.initd.org/tracker/psycopg/ticket/192 In short, a C extension module may cache data from one sub interpreter and then use it in the context of a different sub interpreter causing incorrect or errornous behaviour. The problem with Decimal support in pyscopg falls into this category. It is entirely possible that the OP may have been hitting a similar obscure problem in the database adapter being used. The only real way to ensure that such a problem isn't encountered is to use mod_fastcgi or mod_wsgi daemon mode. In both these hosting solutions for Apache the Django instance can be run in a distinct process and thus one doesn't encounter issues with C extension modules that aren't written to work with multiple sub interpreters properly. Graham --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
