PQ60787: CREATION/DESTRUCTION OF ALARM THREADS RESULTS IN INCREASING THREAD IDS, AND MAY ULTIMATELY RESULT IN JVMCRASH/HANG

 A fix is available

PQ60787,4.0.2: alarm thread creation and destruction causes excessive threads



APAR status
Closed as program error.

Error description
WebSphere Application Server 4.0.2 is experiencing a problem
with excessively high thread ID for the Alarm Thread.
There can be a problem with the Alarm thread management. In 4.02
the alarm thread pool size is set to 1, and if morethan one
alarm fires concurrently, new threads are created to handle the
alarm. At the end of handling the alarm, only one alarm is retur
ned to the pool, while the remaining threads are destroyed.
Alarms are used by WAS to check whether reloadable war files hav
ave been updated. For some applications, such as WPS,there can
be up to 90 alarms created, of which, at any given time10 can
fire. over time, this creation/destruction of alarm threads
may ultimately result in JVM hang/crash
Defects 121091 and 121279
Local fix Problem summary
****************************************************************
* USERS AFFECTED: WebSphere Application Server users who       *
*                 constantly update the war files.             *
****************************************************************
* PROBLEM DESCRIPTION: Problem with the Alarm thread           *
*                      management.                             *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Problem with the Alarm thread management - In 4.02 the alarm
thread pool size is set to 1, and if more than one alarm fires
concurrently, new threads are created to handle the alarm.
At the end of handling the alarm, only one alarm is returned
to the pool, while the remaining threads are destroyed.
Alarms are used by WAS to check whether reloadable war files
have been updated.  For some applications, such as WPS, there
can be up to 90 alarms created, of which, at any given time 10
can fire.  Over time, this creation/destruction of alarm threads
may ultimately result in JVM hang/crash.
Problem conclusion
This defect is being opened with regard to Alarm Thread not
reusing threads thus causing each time one is spawned a thread
to be generated dynamically.  This is fixed by making Alarm
use ThreadPooling.
Temporary fix
\\wasdoc0\
\\wasdoc0\apars\PQ60787\v4.0.2
Comments
APAR information
APAR number PQ60787
Reported component name WEBSPHERE AE AI
Reported component ID 5630A2200
Reported release 400
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Submitted date 2002-05-03
Closed date 2002-05-08
Last modified date 2003-05-15

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Modules/Macros
ALARM          

SRLS

Fix information
Fixed component name WEBSPHERE AE AI
Fixed component ID 5630A2200

Applicable component levels
R400 PSY    UP


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > General
Operating system(s):
Software version: 400
Software edition:
Reference #: PQ60787
IBM Group: Software Group
Modified date: May 15, 2003