Webware for Python

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-02-08-20.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