PQ75760: DEADLOCK WHEN APPLICATION THREAD AND ORPHAN TIMEOUT THREAD ATTMEPT TO CLOSE CONNECTION AT SAME TIME.

A fix is available
3.5.4-3.5.7, 4.0.2-4.0.7: Component cumulative Connection Manager fix

APAR

APAR status
Closed as program error.

Error description
A deadlock is caused when application thread and orphan
timeout thread attempt to close a connection at the same time.
Local fix
Problem summary
****************************************************************
* USERS AFFECTED: Users on WebSphere Application Server 3.5    *
*                 experiencing orphan timeouts on connections  *
*                 which are still in use by the application.   *
****************************************************************
* PROBLEM DESCRIPTION: A JVM deadlock may occur causing the    *
*                      application server to hang.  A JVM      *
*                      thread dump will show a deadlock        *
*                      between one of the application threads  *
*                      and an alarm thread processing an       *
*                      orphan timeout.                         *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The orphan timeout value is designed to clean up connections
leaked by bad application code.  The timer monitors how long
it has been since a connection has been used.  If the orphan
timeout value is too small, this can cause the orphan timer
to close connections which are still in use.  There is a
timing window where this can cause a deadlock between the
application thread and the timeout thread.
Problem conclusion
The synchronization to prevent the JVM deadlock and hang
condition has been corrected.  However, the underlying
problem of a connection being orphaned while it is still in
use by the application still exists.  Users encountering
this scenario should evaluate the amount of time their
connections are being held by their application, and ensure
that the orphan timeout value is larger than this amount of
time.
Temporary fix
Comments
APAR information
APAR numberPQ75760
Reported component nameWEBSPHR HP-UX V
Reported component ID5648C8403
Reported release350
StatusCLOSED PER
PENoPE
HIPERNoHIPER
Submitted date2003-06-27
Closed date2003-07-28
Last modified date2003-07-28

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:APAR is sysrouted FROM one or more of the following:


Modules/Macros
JDBC
APAR is sysrouted TO one or more of the following:Modules/Macros

Fix information

Applicable component levels
R350 PSYUP











Document Information

Product categories: Software, Application Servers, Distributed Application & Web Servers, WebSphere Application Server, General
Software version: 350
Reference #: PQ75760
IBM Group: Software Group
Modified date: 2003-07-28