Chris
On Mar 29, 2004, at 5:18 PM, Roland Dumas wrote:
I'd suggest that's not the issue. I've got a crashing problem and the crash log always points at ODBC.
There are some joins here and there, but are unrelated to crashes. Crashes are unrelated to hits, in fact. Unrelated to taf, table, database.
at a high, there were 3 crashes a day. Haven't had one in a few weeks, though (knocking on wood) but have had lulls before and then a storm of crashes.
On Mar 29, 2004, at 3:12 PM, Chris Millet wrote:
I suspected ODBC simply because Apple's implementation seems, well, less than up-to-snuff. I checked for logs bug haven't found anything useful.
As for active query threads, that is one reason I was asking this question. I'm somewhat new to SQL (I've used Tango/FMP for years) and don't know if a join is considered a single query or multiple. I have read that Witango for OS X can crash under load, but my server just doesn't get that heavy of a load (yet). My thought process was that if a join constituted multiple query threads, then un-joining them might help alleviate the problem.
I'll test out the joins as you've suggested and let you know what happens.
Thanks, Chris
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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