Roger, Give Webware from the tip of CVS a try. From perusing the CVS tree, it looks like many optimizations and improvements have been made to MiddleKit between 0.7 and now.
I can't say for sure that your problem has been fixed, but it's worth a try. And in any case, any attempt to fix the problem should start with the most up-to-date version of MiddleKit. I hope I'm wrong, but unfortunately I suspect that MiddleKit still needs some further work in order to be fully thread-safe. In that case, you may be able to work around thread-safety issues by using your own threading.RLock objects in strategic places. - Geoff > -----Original Message----- > From: Roger Haase [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, August 21, 2002 1:03 AM > To: [EMAIL PROTECTED] > Subject: [Webware-discuss] MiddleKit Threading Problem? > > > I have finally had a repeat of the problem I last wrote about > on July 20. I > have a web page that is trying to load several images at once > similar to: > > <img src="ShowPix?pid=4&tn=160"> > > The ShowPix.py servlet does several MySQL calls, then loads a > .jpg image from > the filesystem, messes with it, and writes out the modified image. > > I haven't tried to do it yet, but I think I will be able to > recreate the > problem in a simple environment by initiating multiple > servlets all of which > try to access the same MySQL table row which is not yet > present in any cache. > > In the latest episode, I had been in the final stages of > testing a new > servlet for about 20 minutes, when I ran the servlet that creates > the web page containing the ShowPix transactions. Of 5 > images, only the > second one succeeded, the other four failed on the > MiddleObject.py assertion > error: > assert len(cache)+1==len(row) > > I had modified MiddleObject.py just before the failing line: > if len(cache)+1<>len(row): > log = open('/home/roger/MiddleObject.txt', 'a') > log.write('cache:' + str(cache) + '\n') > log.write('row:' + str(row) + '\n') > log.close() > > The output from the above is: > cache:[<unbound method Root.setName>, <unbound method > Root.setLinuxName>, > <unbound method Root.setName>, <unbound method Root.setLinuxName>] > row:(1L, 'D:/Pix/', '/mnt/win_d/Pix/') > > The "row" above is correct: serialNum 1, my Windows root > directory name, and > the same root linuxName used when I run under Linux. The > cache seems to have > been duplicated, with Root.setName and Root.setLinuxName > appearing twice. > The "cache" value is persistent and all attempts to access > that row continue > to fail until the AppServer is restarted. > > Note that the second transaction succeeded, as if the first > transaction was > stopped for I/O, the second blew past it, and the first transaction > permanently trashed the "cache" when it resumed. This is > very similar to the > circumstances that occurred on 7/19 when 6 of 7 similar > transactions failed > with the second one succeeding. > > Further information is at: > > http://www.users.qwest.net/~haaserd/Webware/Error-ShowPix.py-0 2-08-20.html http://www.users.qwest.net/~haaserd/Webware/MiddleObject.py I am running Webware version 7 with one fix to ServletFactory.py for another threading problem. I would be happy to test any untested coding suggestions from any MiddleKit experts. I am pretty sure I can code a simple example which will replicate the problem after a finite number of tries. Roger Haase ------------------------------------------------------- This sf.net email is sponsored by: OSDN - Tired of that same old cell phone? Get a new here for FREE! https://www.inphonic.com/r.asp?r=sourceforge1&refcode1=vs3390 _______________________________________________ Webware-discuss mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/webware-discuss ------------------------------------------------------- This sf.net email is sponsored by: OSDN - Tired of that same old cell phone? Get a new here for FREE! https://www.inphonic.com/r.asp?r=sourceforge1&refcode1=vs3390 _______________________________________________ Webware-discuss mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/webware-discuss
