[mod_python] session locking causes hang with mpservlets

My previous post didn't address the issue correctly.
I made some error logging in mpservlets to see where things stop.  In 
this case, the internal redirect is not being called.  It never gets 
that far:
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] HANDLER - 
calling auth
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] HANDLER - 
calling prep
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] PREP - 
clearing self.__out
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] PREP - setting 
self.form
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] PREP - calling 
__load_vars()
[Sat Mar 26 14:34:02 2005] [error] [client 192.168.1.127] PREP - setting 
self.session

-- end of log --

We never see "Redirecting to login" in the log.

So, the initial establishment of the session is failing, due to locking.

I have no idea why.

Scott


Graham Dumpleton wrote:

> Try adding:
>
>   self.session.unlock()
>
> just before the internal redirect and see what happens.
>
> I don't believe this should be required as mpservlets is using
> its own internal redirect which actually saves the session before
> doing the real internal redirect.
>
> Anyway, this "experiment" might at least help you to understand
> things better.
>
> BTW, I am assuming when you say "make session lock=0", you mean
> setting "use_session" appropriately. Is that correct?
>
> Graham
>
> On 27/03/2005, at 7:29 AM, Scott Chapman wrote:
>
>> Using linux - prefork mpm.
>> I set my httpd.conf:
>> StartServers 1
>> MinSpareServers 1
>> MaxSpareServers 0
>> MaxClients 1
>> MaxRequestsPerChild  0
>>
>> for this test run.
>>
>> Here's my UberServlet:
>> -------------- snip --------------
>> from mod_python.servlet import Servlet
>>
>> class uberservlet(Servlet):
>>     use_session = True
>>
>>     def respond(self):
>>         self.req.log_error('Responding')
>> methodName=self.req.uri[:len(self.req.uri)-len(self.req.path_info)][1:]
>>         self.req.log_error('methodName: '+methodName)
>>         if methodName == 'index':
>>             self.req.log_error('Redirecting to login')
>>             self.internal_redirect('/login')
>>         if methodName == 'login':
>>             self.req.log_error('Doing login')
>>             self.writeln ('<h1>login_here</h1>')
>>             return True
>>
>>     def wrapup(self):
>>         Servlet.wrapup(self)
>> -------------- snip --------------
>> When I make Sesssion lock=0, it doesn't hang.
>> When I don't set lock = 0 (the default) it hangs when trying to 
>> establish the session:
>>   self.session = Session.Session(self.req, timeout=self.session_timeout)
>>
>> What problems do I look forward to if I run with lock=0?
>>
>> Quoting Grisha:
>> "One thing you may try as an experiment is to disable session locking
>> (Session(lock=0)). It will still use locking for access to the DBM, 
>> but it won't lock individual sessions."
>>
>> Grisha calls this "an experiment".  Can anyone tell me why locking is 
>> failing and what will happen if I run with locking off?
>>
>> TIA,
>> Scott
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>
>
>
>