[Webware-discuss] Webware/msdb/FreeTDS SegFault (was: AppServer core dump)

Geoff Talvola gtalvola at nameconnector.com
Thu Aug 23 09:50:56 EDT 2001


At 10:14 AM 8/23/01 +0200, Mark Gebhardt wrote:
>Hi all
>
>BACKGROUND:
>I am running Python Webware (0.5.1-rc3)( RedHat Linux 7.0 / Apache / WebKit
>/ ThreadedAppServer) and using it (via intermediate Python classes (and Tom
>Osborne's Python msdb library (ex Datautils-0.1) , using FreeTDS (0.52) to
>access MS SQL server on a remote Windows 200 box.
>
>PROBLEM:
>Most of the time this works just fine. However (and here's the thing)
>sometimes it all falls over in a heap with a Segmentation Fault (see error
>message below). It SEEMS that this only occurs when I try to query SQL
>server such that it returns no records.
>
>THOUGHTS:
>My current assumption is that the Seg Fault is coming out of either msdb or
>FreeTDS (and I will spend much time today trying to repeat the SegFault
>without using Webware in order to verify this).

You could try using mxODBC to access SQL Server instead of the library 
you're using.  I have no experience with mxODBC, so I can't say how easy it 
would be or what other problems it might cause.

As far as fault tolerance goes, it's not something Webware developers have 
put much effort into yet, mostly because it just seems to keep on running 
for most people.  I personally have never had the appserver crash on 
me.  Your best bet in the short term is to try to fix the crashes in your 
db library, and failing that, fix up Monitor.py so that it does its job 
properly.  Longer term, we need to think about how to add some real fault 
tolerance to the Webware architecture.


--

- Geoff Talvola
   gtalvola at NameConnector.com



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