It may be the ODBC or JDBC layer.  That code is loaded by the app server and can cause 
the app server to crash.

Have you checked /Users/witango/Library/Logs/CrashReporter for crash logs?

In Witango.log, can you see how many active query threads are listed before the crash?

I have often seen more than one thread active before a crash.  This leads me to 
believe the crashes were due to thread problems (e.g, a non-thread safe system call 
like strftime on OS X 10.2, for which the app server has a work-around but J/ODBC may 
not).  Thread problems could explain the apparent inconsistency with the crashes.

However, I think using Witango.log to determine whether or not a crash was 
thread-related is difficult.  The app server does not seem write out all Witango.log 
entries immediately (for performance reasons?).  A crash may result in missing 
messages from the end of Witango.log.

One possible test:  Make a TAF containing only a DirectDBMS action with a SQL 
statement that makes a join.  Request the TAF a lot -- enough so the app server spends 
a few minutes with multiple active query threads.  See if it crashes.  Then replace 
the SQL statement with one that doesn't do a join and hit it again.  If it looks like 
avoiding joins helps with crashes, you could use SQL views instead of defining joins 
in your Witango code.

- Jeff



>if its a join making the server crash it sounds more like your database is
>causing the crash instead of witango.
>
>you might check if it has any kind of crash log or debugging output you can
>turn on.
>
>----- Original Message -----
>From: "Roland Dumas" <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Monday, March 29, 2004 12:26 PM
>Subject: Re: Witango-Talk: Can SQL joins make OS X server crash?
>
>
>> witango always writes to the witango crash log when it crashes. It
>> tells what's going on with each thread. I've got a 100% record of
>> crashes.
>>
>> On Mar 29, 2004, at 12:23 PM, Chris Millet wrote:
>>
>> > Nothing. Zip. Zero. Zilch.
>> >
>> > (actually it does say something, but the only entries are for known
>> > instances where we have been able to trace the problem)
>> >
>> > Chris
>> >
>> > On Mar 29, 2004, at 2:13 PM, Roland Dumas wrote:
>> >
>> >> what's your crash log say?
>> >>
>> >> On Mar 29, 2004, at 12:08 PM, Chris Millet wrote:
>> >>
>> >>> Can SQL joins make the server crash on OS X?
>> >>>
>> >>> I don't know enough about why the server crashes, only that it does
>> >>> crash (in)consistently after running apps with joins in the SQL
>> >>> query. I have combed through the apps several times and have made
>> >>> them as efficient as I can. I am even using DBMS actions instead of
>> >>> search actions (they are faster), but nothing seems to help.
>> >>>
>> >>> The crashes, like others I have read about on OS X, work fine most
>> >>> times but begin to crash seemingly on a whim.
>> >>>
>> >>> Any insight would be greatly appreciated.
>> >>>
> > >>> Chris

-- 

Jeff Bohmer
VisionLink, Inc.
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www.visionlink.org
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