[Zope] Multithreading sessions

[Manuel Vazquez Acosta]

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This is relevant:
http://docs.python.org/api/threads.html
http://www.pyzine.com/Issue001/Section_Articles/article_ThreadingGlobalInterpreter.html

But notice some C extensions do allow concurrency by releasing the GIL.
Most I/O operations in the standard library do that. And probably the
network library used by python to connect to MySQL does that too.

However, if I got everything Jon explained, the problems happens even
with several DB servers. :?

Best regards,
Manuel.

Sours, Kevin wrote:
> What it sounds like is that Python is using a "sequential" threading
> model.  I don't know about Python in particular, but some languages
> implement a sequential model internally so that multithreaded programs
> will run correctly (if not effeciently) in the absense of whatever
> thread libraries the language uses for normal threading.
> 
> As an aside, something I learned the hard way is that Python doesn't
> thread very well.  The documentation talks a lot about threading, but in
> most instances only one thread can run at a given time (it should still
> swap between threads, though).  I never saw any benefit to increasing
> z-server-threads beyond 4 -- all the extra threads are going to do is
> consume memory.  If you need get real concurrency (for example to make
> use of additional processors) you need to run multiple zope processes.
> Kevin
> 
> -----Original Message-----
> From: zope-bounces at zope.org [mailto:zope-bounces at zope.org] On Behalf Of
> Jon Emmons
> Sent: Friday, May 23, 2008 8:10 AM
> To: 'Jaroslav Lukesh'; zope at zope.org
> Subject: RE: [Zope] Multithreading sessions
> 
> Jaroslav and everyone,
> 
> I have made the changes Jaroslav suggested and I cannot get Zope to
> serve even 2 sessions simultaneously.
> 
> In our testing, one client will start a query to the data servers.
> Another will try to simply get the logon page to be served.  Zope will
> simply sit there and wait until the DB returns its results for the first
> user before doing anything at all for the second.  The 2nd user is not
> hitting the DB server.  The python script accessing the data is waiting
> for the results for the first user.  Could python be the problem?
> 
> I am running python 2.4.4.
> 
> Is it possible that I missed a flag or something when I build the Zope?
> 
> Thanks for your suggestions so far, but I think I have missed a
> fundamental setup step that allows zope to multithread sessions.
> 
> If I were echoing what was being served to the clients, shouldn't I see
> it interwoven?  I don't, it is always (client 1's results) then (client
> 2's results)... very atomic.
> 
> Thanks again,
> 
> Jon Emmons
> 
> 
> 
> -----Original Message-----
> From: Jaroslav Lukesh [mailto:lukesh at seznam.cz]
> Sent: Friday, May 23, 2008 9:37 AM
> To: Jon Emmons; zope at zope.org
> Subject: Re: [Zope] Multithreading sessions
> 
> Hi Jon,
> 
> I use 24 zserver-threads and I have here defined number of ZoDB
> connections
> (pool-size):
> 
> in your instance etc/zope.conf look for that section:
> 
> <zodb_db main>
>     # Main FileStorage database
>     <filestorage>
>       path $INSTANCE/var/Data.fs
>     </filestorage>
>     mount-point /
>     cache-size 1000
>     pool-size 24
> </zodb_db>
> 
> Please pay attention, if you have bunch of cache, your RAM shoul be
> exhausted.
> 
> Regards, JL.
> 
> ----- Original Message -----
> From: "Jon Emmons" <jon.emmons at earthwavetech.com>
> 
> 
>> I had already gone into zope.conf and added the line:
>>
>> zserver-threads 10
>>
>> This seemed to have no effect.  Is that what you mean?
>> You think I should bump it higher?  100 maybe?
> 
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