RE: [Wrapper-user] JVM exited unexpectedly

[Bill L. <bli...@to...>]

Hi Paul-

I am also working an issue where my app JVM exits for no apparent cause,
anywhere between 15 minutes and more than 1 month after startup. I have
not found the cause yet, but with lots of help from Leif, I believe the
cause is related to a deadlock and I have settled into the following
configuration:

-Wrapper version 3.0.5 (earlier versions had a bug where the pause was
short enough that sometimes the requested thread dump would be
truncated).
-Additions to the wrapper configuration file:
  wrapper.request_thread_dump_on_failed_jvm_exit=3Dtrue
  wrapper.debug=3Dtrue
-Set the loglevel for both the console and logfile to DEBUG.
-Start the application from a console instead of from a service (wrapper
-c ...). A thread dump can only be generated if the JVM is attached to a
console.

I am waiting for the next failure to generate a complete thread dump, so
I cannot tell you how helpful this will be, but I am hopeful.

One other thing. You mention garbage collection (GC). There are times
during GC when the JVM simply stops doing anything else, including
servicing Wrapper pings. These pauses can vary in length, depending on a
number of things including the GC strategy you are employing. One
condition that has a dramatic effect on GC pause time is whether or not
any of the JVM is in virtual memory. In my app, when any part of the JVM
goes into virtual memory, GC pause time can increase by two orders of
magnitude. I have seen pause times of over 90 seconds, which, depending
on your wrapper settings, is more than enough to cause the wrapper to
restart.

I hope this helps.

-Bill Littman


> -----Original Message-----
> From: Paul Casanova [mailto:cas...@au...]=20
> Sent: Tuesday, November 04, 2003 11:08 PM
> To: wra...@li...
> Subject: [Wrapper-user] JVM exited unexpectedly
>=20
>=20
>=20
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>=20
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> Hi all,
>=20
> This problem is not caused by the Java Service Wrapper - I=20
> just need some
> help to extract some diagnostics please!
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> I have a problem where my JVM exits about once a week (not at=20
> a consistent
> time) on Windows 2000 Advanced Server, JDK 1.3.1_09.
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> This is a new box - dual P4 2.4GHz with hyperthreading, 6.3GB=20
> of RAM, and 2
> of the Java processes happily consume 1600MB of RAM each=20
> under the watchful
> eye of the Java Service Wrapper.  Thankfully the Java Service=20
> Wrapper kicks
> things off again when the JVM exits.
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> Before utilising the Java Service Wrapper, srvany (MS -=20
> yuck!) was used to
> control the application.  It did die every now and then, and=20
> normally we
> could explain it with a Dr Watson dialog saying that Java had=20
> caused an
> access violation etc.  We don't seem to be getting the Dr=20
> Watson errors,
> which is strange.  Peak RAM usage was around 4.25GB, which=20
> indicates that
> the Java processes had been hitting the ceiling of 1600MB,=20
> but they should
> garbage collect and get on their way.
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> Currently the wrapper log file level is set to WARN, syslog=20
> is set to FATAL
> and console is set to FATAL.  As it may be another week=20
> before I see this
> happen again, I'm not keen on trial and error of logging=20
> levels to dump out
> more info next time the JVM decides to die - debug could=20
> result in huge
> files without need.
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> What can I do to get some info about what happened when the=20
> JVM exited?
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> Thanks in advance,
>=20
> Paul Casanova
>=20
>=20
>=20
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