We're now encountering a "wedge" every couple of days or so on our test
servers (RedHat Linux 6.2, Webware 0.7, Apache 1.3.x with mod_webkit) and
it's starting to worry us.  So if there's progress on the wedge-elimination
front, we'd love to hear about it.  And if we can help, let me know.
Caveat: We're developing WITH Webware, but don't feel competent yet to make
substantive changes to the core code.

The symptoms are that NO webkit threads seem to respond to browser requests.
Sometimes there's a core dump, which gets labeled with the pid, I'm assuming
(such as core.34172, where 34171, 34170, etc. are Webkit processes.  Loading
the core in the debugger tells me that ThreadedAppServer encountered a
segmentation fault (signal 11).  There's nothing labeled in the stack trace,
just memory addresses, so I can't tell what function was executing.  netstat
reports that there's a server listening (we're using 8086 for WebKit), and
in fact, we can do 'telnet localhost 8086' and get connected.  (Of course,
we can't do more at that point because it's looking for request data
marshalled into some structure we don't know how to recreate from the
command line!)  But at least there's a listening socket.

When this occurs, stopping and starting the ThreadedAppServer clears the
problem, but the processes need to be 'kill -9'ed before they'll die.

I'd be grateful for any ideas on how to figure out where this problem is
coming from, how to fix it, etc.

I wish I had better information from the core dump (which doesn't always
happen), so if we need to instrument Webware or even Python to get better
stack traces, we could try that.  My past experiences with turning on
voluminous debug information, though, is that it slows things down enough
that timing-related bugs don't show up anymore.

We MAY be able to install 0.8 on the test system, but my handlers would like
some statement from me BESIDES "I hope the upgrade will fix this problem."
They keep quoting the title of a recent business book: _Hope Is Not a
Strategy_.

Cheers!
--
David Hancock | [EMAIL PROTECTED] | 410-266-4384


-----Original Message-----
From: Geoffrey Talvola [mailto:[EMAIL PROTECTED] 
Sent: Thursday, March 06, 2003 9:41 AM
To: 'Hancock, David (DHANCOCK)'; [EMAIL PROTECTED]
Subject: RE: [Webware-discuss] help evaluating WebWare


Hancock, David (DHANCOCK) [mailto:[EMAIL PROTECTED] wrote:
> We have had some occurrences of threads seeming to wedge 
> (mentioned just
> recently on the list), and we're trying to figure out why.  

I'd like to improve WebKit so that you can enable a "DebugThreads" flag.  It
would then detect when a thread is wedged (i.e. hasn't finished its
transaction within some configurable timeout) and send a warning email.
Perhaps it would also add an additional thread to the thread pool to make up
for the wedged thread.  Finally, it would be nice if the wedged thread
didn't prevent the appserver from shutting down cleanly.

Any other ideas?  I'll probably try to implement this within the next couple
days.

- Geoff


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