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PM60129: PERFORMANCE IMPROVEMENT FOR DISK CACHE ID LOOKUP

Fixes are available

8.0.0.4: WebSphere Application Server V8.0 Fix Pack 4
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
8.5.0.1: WebSphere Application Server V8.5 Fix Pack 1
8.0.0.5: WebSphere Application Server V8.0 Fix Pack 5
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
8.5.0.2: WebSphere Application Server V8.5 Fix Pack 2
8.0.0.6: WebSphere Application Server V8.0 Fix Pack 6
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
8.0.0.7: WebSphere Application Server V8.0 Fix Pack 7
8.0.0.8: WebSphere Application Server V8.0 Fix Pack 8
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server

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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



Document information

More support for: WebSphere Application Server
General

Software version: 7.0

Reference #: PM60129

Modified date: 03 February 2015