Re: [Zope] Florent Guillaume's database Conflict Error on session objects patch not working ?
yacine chaouche wrote at 2007-2-3 13:55 +0100: ... Once I understood the publishing process, I edited the publish.py file to display a traceback of every raised exception before retrying the request. Thus, I could see that there were database conflict errors that were raised. Usually, such conflicts are logged -- without a need to change Publish.py. ... When I do not use session, in my own code, I have no errors. This is supposed to prove that the conflict error comes from the use of the session object in my code. This is not supposed to prove that another plugin is using it anyway... Sorry, I did not read your message carefully enough. -- Dieter ___ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )
Re: [Zope] Florent Guillaume's database Conflict Error on session objects patch not working ?
Hi Dieter, What part of what I said don't you understand ? I will try to make it clearer here : The referenced links above do not refer to conflict errors but to XMLRPC and strace. Then, too, I had great difficulties to understand your problem... Yes, when I posted the XMLRPC and strace message on the list I did not know yet the publishing process and everything. So I thought that zope just went crazy pretending to receive new requests. In reality, it was the same request that was retried over and over again until no exception was raised. Once I understood the publishing process, I edited the publish.py file to display a traceback of every raised exception before retrying the request. Thus, I could see that there were database conflict errors that were raised. I am aware that conflicts occure up to 20% of the time, but in my case it is almost 100% in this specific situation ! You can easily achieve almost sure conflicts. We did once with a frame based solution: I do NOT use frames. If I do not use the session object in my code, I have no errors at all and everything just goes fine. Then, you are using some add-on component that *is* using the session object. That's what I am saying : in my code I need to use the session to store objects. When I use the session, in my code, not in a plugin or so, in my own code, I have errors. When I do not use session, in my own code, I have no errors. This is supposed to prove that the conflict error comes from the use of the session object in my code. This is not supposed to prove that another plugin is using it anyway... Thanks, Y.Chaouche 2007/2/2, Dieter Maurer [EMAIL PROTECTED]: yacine chaouche wrote at 2007-2-2 14:39 +0100: ... As discussed here : http://mail.zope.org/pipermail/zope/2007-January/170151.html and continued here : http://mail.zope.org/pipermail/zope/2007-January/170156.html I am experiencing issues regarding a database ConflictError on session objects. Hm, I have issues with your problem descriptions... The referenced links above do not refer to conflict errors but to XMLRPC and strace. Then, too, I had great difficulties to understand your problem... ... It is not a ReadConflictError, nor a WriteConflictError. It is a ConflictError: database conflict error. A ConflictError is in fact a WriteConflictError. I am aware that conflicts occure up to 20% of the time, but in my case it is almost 100% in this specific situation ! You can easily achieve almost sure conflicts. We did once with a frame based solution: All frames in a frameset accessed the session and tried to store some information in it. As the browser requested the frames concurrently, there was a very high probablity for conflicts. In our case, there was no real need for most of the frames to access the session. Removing the unnecessary accesses removed the problem. But, if the frames had a real need to store something in the session, we would have to use persistent subobjects in the session to separate the access of the various frames into different objects. If I do not use the session object in my code, I have no errors at all and everything just goes fine. Then, you are using some add-on component that *is* using the session object. If the session is not used, there will be no session related conflict error. Any idea on how to debug this ? Florent, maybe ? someone help me ! I am stuck on this for 2 weeks now. You could try to delete /temp_folder/session_data temporarily (it will be recreated on the next Zope startup) to find out which component does use sessions. -- Dieter ___ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )
Re: [Zope] Florent Guillaume's database Conflict Error on session objects patch not working ?
On 2/3/07, yacine chaouche [EMAIL PROTECTED] wrote: I am experiencing issues regarding a database ConflictError on session objects. Can you detail all the various getSesion and setSession methods of: http://mail.zope.org/pipermail/zope/2007-January/170167.html I use zope 2.9.0 python 2.4.2. It's worth trying the latest of each of those. Cheers Michael ___ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )
[Zope] Florent Guillaume's database Conflict Error on session objects patch not working ?
Hi all, As discussed here : http://mail.zope.org/pipermail/zope/2007-January/170151.html and continued here : http://mail.zope.org/pipermail/zope/2007-January/170156.html I am experiencing issues regarding a database ConflictError on session objects. I use zope 2.9.0 python 2.4.2, and the code of the MultiDB support has been patched (as suggested by Florent Guillaume) http://mail.zope.org/pipermail/zodb-dev/2006-January/009737.html My main concern is to debug my application where, on every couple of requests coming from two different browsers at the same time (before the first request is , one of them wins and the other always fails and raises a conflict error. It is not a ReadConflictError, nor a WriteConflictError. It is a ConflictError: database conflict error. I am aware that conflicts occure up to 20% of the time, but in my case it is almost 100% in this specific situation ! If I do not use the session object in my code, I have no errors at all and everything just goes fine. Any idea on how to debug this ? Florent, maybe ? someone help me ! I am stuck on this for 2 weeks now. NOTE : I do not use Zeo, nor frames. Thanks, Y.Chaouche ___ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )
Re: [Zope] Florent Guillaume's database Conflict Error on session objects patch not working ?
yacine chaouche wrote at 2007-2-2 14:39 +0100: ... As discussed here : http://mail.zope.org/pipermail/zope/2007-January/170151.html and continued here : http://mail.zope.org/pipermail/zope/2007-January/170156.html I am experiencing issues regarding a database ConflictError on session objects. Hm, I have issues with your problem descriptions... The referenced links above do not refer to conflict errors but to XMLRPC and strace. Then, too, I had great difficulties to understand your problem... ... It is not a ReadConflictError, nor a WriteConflictError. It is a ConflictError: database conflict error. A ConflictError is in fact a WriteConflictError. I am aware that conflicts occure up to 20% of the time, but in my case it is almost 100% in this specific situation ! You can easily achieve almost sure conflicts. We did once with a frame based solution: All frames in a frameset accessed the session and tried to store some information in it. As the browser requested the frames concurrently, there was a very high probablity for conflicts. In our case, there was no real need for most of the frames to access the session. Removing the unnecessary accesses removed the problem. But, if the frames had a real need to store something in the session, we would have to use persistent subobjects in the session to separate the access of the various frames into different objects. If I do not use the session object in my code, I have no errors at all and everything just goes fine. Then, you are using some add-on component that *is* using the session object. If the session is not used, there will be no session related conflict error. Any idea on how to debug this ? Florent, maybe ? someone help me ! I am stuck on this for 2 weeks now. You could try to delete /temp_folder/session_data temporarily (it will be recreated on the next Zope startup) to find out which component does use sessions. -- Dieter ___ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )
