I wasn't able to check for dead threads - My symptom was that the tomcat process
would 'hang' and no longer process connections.
I never got it to crash per se, but it sure stopped on me real good...
Increasing the pool size resolved the problem, specifically the following
parameters (neatly copied from the tomcat users guide)
<Parameter
name="max_threads"
value="30"/>
<Parameter
name="max_spare_threads"
value="20"/>
<Parameter
name="min_spare_threads"
value="5" />
The values were arbitrary - I stuck mine up to max_threads = 200,
max_spare_threads=20, min_spare_threads=20
and lo - the hang problem went away.
It seems to me that when tomcat (3.2.1) get's pressed for thread resources, it
doesn't do a very good job of recovering from this.
I would have thought that having a min_spare_threads set to some non-zero value,
that there would still be some spare threads for clean up
work to be performed but, as far as I can tell, when you max out your threads,
your stuck pending a reboot.
-Thom
Hunter Hillegas wrote:
> How can I check to see if I have a lot of "dead threads"?
>
> Hunter
>
> > From: "Devon Ziegler" <[EMAIL PROTECTED]>
> > Reply-To: [EMAIL PROTECTED]
> > Date: Mon, 21 May 2001 16:43:04 -0400
> > To: <[EMAIL PROTECTED]>
> > Subject: RE: 3.2.1 Dies
> >
> > Interesting.....used up all free threads.....increase thread pool.....
> > shouldn't users just have to wait for a free thread if they hit the pool
> > limit? Increasing it should let more requests be handled simultaneously,
> > but how would it help longevity? I'm not saying it won't. Just skeptical.
> >
> > That said, I seem to "lose" threads with tomcat 3.2.1 on Linux 2.2.14 using
> > Sun's 1.3 JDK. What I mean is that "dead" threads pile up WELL in excess of
> > the thread pool limit. These threads don't seem to handle requests any
> > more. Tomcat slows down quite noticeably too. I'm not sure I have ever
> > left it up long enough to know if it might just die after enough threads
> > "pile" up(well, it definitely would when it hit the OS' thread limit). Are
> > you seeing far more threads than you would expect (well in excess of the
> > pool size)? Maybe we are suffering from the same malady.
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