PM60129: PERFORMANCE IMPROVEMENT FOR DISK CACHE ID LOOKUP

Fixes are available

APAR status

Closed as program error.

Error description

Javacore shows a performance issue with following callstack

at java/util/HashSet.contains(HashSet.java(Compiled Code))
at
com/ibm/ws/cache/HTODDependencyTable.containsCacheId(HTODDepende
ncyTable.java:261(Compiled Code))
at
com/ibm/ws/cache/HTODDynacache.isCacheIdInAuxDepIdTable(HTODDyna
cache.java:3433(Compiled Code))

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  All users of IBM WebSphere Application      *
*                  Server using dynacache with disk offload    *
*                  and cached objects with hundreds of         *
*                  dependency IDs.                             *
****************************************************************
* PROBLEM DESCRIPTION: Determining if a cache id exists on     *
*                      disk is a performance bottleneck.       *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Dynacache maintains a table of dependency IDs that contains a
list of associated cache IDs.  Dynacache is using a linear
search to find a cache id in the table.  This is inefficient
and costly.

Problem conclusion

Dynacache has changed how it maintains its table mapping of
dependency IDs to cache IDs to improve the searching of a
cache ID.

A new JVM custom property is being introduced to activate this
new method of searching for a cache ID on disk.  Using this
feature does have a slight increase in the heap usage of
dynacache.

To activate this feature define and set to true the following
property:
com.ibm.ws.cache.CacheConfig.htodDependencyCacheIndexEnabled

Click Servers > Server Types > WebSphere application servers >
server_name, and then, under Server Infrastructure, click Java
and process management > Process definition > Java virtual
machine > Custom properties

The fix for this APAR is currently targeted for inclusion in
fix packs 7.0.0.25, 8.0.0.4 and 8.5.0.1.  Please refer to the
Recommended Updates page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PM60129
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2012-03-09
Closed date
2012-05-15
Last modified date
2015-02-03

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

Fix information

Fixed component name
WEBS APP SERV N
Fixed component ID
5724H8800

Applicable component levels

R700 PSY
UP
R800 PSY
UP
R850 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 October 2021

Tips

PM60129: PERFORMANCE IMPROVEMENT FOR DISK CACHE ID LOOKUP

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R700 PSY

R800 PSY

R850 PSY

Document Information

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