[Zope] Kid clicking and Zope thread deadlock

[Brian Lloyd]

> "Kid clicking" is a technical term used in multimedia game programs, 
> referring to firing multiple click events quickly. The most 
> scary part is 
> that under intense clicking, a multi-threaded program would go into 
> dead-lock.
> 
> I have a Zope application running. When I kid-click on one button, it 
> actually locks Zope up. This error does not happen when I run Zope in 
> single-thread mode. So, for the bug seems to come from Zope thread 
> dead-locking.
> 
> <snip>
> 
> My Zope is 2.1.6. More info: it happens both with Netscape 
> and IE. More 
> info: when kid clicking on the webpage, actual requests are 
> sent to the Zope 
> server, I see from the terminal 4 lines about
> 
> 2000-06-30T00:29:43 PROBLEM(100) ZSybaseDA Changed database 
> context to 
> 'master'.
> Changed database context to 'mydatabase'.
> 
> and it then goes into deadlock. Not sure whether it's Sybase or Zope 
> problem.

The quick way to determine this: install a fresh Zope without 
SybaseDA installed and see if you can reproduce the kid-clicking 
behavior.

Another thing potentially to look at: there is problem with 
Sybase connections that I have run into before where if you 
have a request that runs a transactional query, then a non-
transactional query, then trys another transactional query 
you get a hang :(  I don't know if this could be the case 
here, but if so you might want to look here for more info:

http://classic.zope.org:8080/Collector/1059/view




Brian Lloyd        brian@digicool.com
Software Engineer  540.371.6909              
Digital Creations  http://www.digicool.com