PQ66150: EXTENSIVE GARBAGE COLLECTION OCCURING WITH MARK STACK OVERFLOW

A fix is available
WebSphere Application Server Version 3.5 Fix Pack 7 (3.5.7)

APAR

APAR status
Closed as program error.

Error description
Extended GC times associated with "mark stack overflow".
Heap- roots analysis shows large trees associated with com/ibm/s
ervlet/util/SimpleHashtable (WebSphere).
Local fix
Problem summary
****************************************************************
* USERS AFFECTED: WebSphere Application Server installations   *
*                 experiencing large Garbage Collections.      *
****************************************************************
* PROBLEM DESCRIPTION: Extended Garbage Collections (GC)       *
*                      associated with Mark Stack overflow.    *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Extended Garbage Collection times associated with Mark Stack
Overflow are being executed due to an imbalanced Hashtable
object.  When the hashtable was reaching its peak capacity
and required resizing, the hashtable was not being rehashed
to properly take advantage of this increased capacity.  The
lack of rehashing caused poor performance relating to seek
times for objects in the hashtable.
Problem conclusion
Modified the WebSphere internal Hashtable implementation
to properly rehash when the hashtable is expanded.
Temporary fix
Comments
APAR information
APAR numberPQ66150
Reported component nameWAS ADVANCED AI
Reported component ID5648C8400
Reported release350
StatusCLOSED PER
PENoPE
HIPERNoHIPER
Submitted date2002-09-12
Closed date2002-09-12
Last modified date2002-09-13

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:

PQ66175

Modules/Macros
ENGINE
APAR is sysrouted TO one or more of the following:PQ66175Modules/Macros

Fix information
Fixed component nameWAS ADVANCED AI
Fixed component ID5648C8400

Applicable component levels
R350 PSYUP











Document Information

Product categories: Software, Application Servers, Distributed Application & Web Servers, WebSphere Application Server, General
Software version: 350
Reference #: PQ66150
IBM Group: Software Group
Modified date: 2002-09-13