[Zope] Zope crashes on request of certain page

[Floyd May]

Sven Jacobs wrote:
> Dear Zope list,
> 
> I have a serious problem with Zope. Every time a certain page is 
> requested by a web browser for the second or third time (first time 
> always works) the whole Zope server crashes :-(
> 
> The only thing special about this page are calls of external Python 
> methods from a custom extension. These methods don't do any special 
> magic. They just open a MySQL database (using the MySQLdb module version 
> 0.9.1) and return some HTML output.
> 
> I was able to catch a somewhat informative error message when Zope was 
> running in debug mode:
> 
> 2006-03-27T12:18:57 PANIC(300) z2 Startup exception
> Traceback (innermost last):
>   File /opt/zope/z2.py, line 495, in ?
>     (Object: ZLogger)
>   File <string>, line 1, in ?
>   File /opt/zope/lib/python/Zope/__init__.py, line 37, in ?
>   File /opt/zope/lib/python/ZODB/FileStorage.py, line 202, in __init__
>   File /opt/zope/lib/python/ZODB/lock_file.py, line 29, in lock_file
> StorageSystemError: Could not lock the database file.  There must be
> another process that has opened the file.
> 
> Operating system is SuSE Linux 8.0, Zope version is 2.5.0, Python 2.2, 
> MySQL 3.23.48. I know, pretty old but upgrading any of these software 
> components should be avoided due to emerging costs unless absolutely 
> necessary!
> 
> So if you have any idea how to fix this problem besides "upgrade to the 
> newest versions" I would be glad to here from you!
> 
> Thank you very much!
> 

Use a MySQL database adapter in Zope, and use ZSQL Methods to retrieve 
data from the database.
See here:
http://www.plope.com/Books/2_7Edition/RelationalDatabases.stx

HTH!

-- 
Floyd May
Senior Systems Analyst
CTLN - CareerTech Learning Network
fmay at okcareertech.org