IBM Support

PH12606: STORE APPLICATION CLASSES IN SHARED CLASS CACHE TO IMPROVE SERVER STARTUP

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You can track all active APARs for this component.

 

APAR status

  • Closed as new function.

Error description

  • Only product classes were stored in the IBM JDK shared class
    cache.  By adding application classes to the shared class
    cache, applications can start up faster on subsequent server
    starts.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server                                      *
    ****************************************************************
    * PROBLEM DESCRIPTION: Improve startup time and reduce memory  *
    *                      footprint using java class sharing.     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Since WebSphere Application Server version 6.1, Java class
    sharing -- IBM JVM option "-Xshareclasses" -- is enabled by
    default for Application Server, Node Agent, and Deployment
    Manager processes in order to improve startup time and
    reduce memory footprint (1, 2).
    APAR PH12606 extends Java class sharing support within
    WebSphere Application Server to include Java
    Enterprise Edition applications, shared libraries and isolated
    resource providers. Specifically, the classloader types which
    load these entities have been upgraded to store and load
    class definitions to and from the server's Java shared class
    cache.
    This new application class sharing support introduced by APAR
    PH12606 will enable and disable according to the value of the
    "-Xshareclasses" option configured for each server process
    type.  Visit Knowledge Center topic "Tuning the IBM virtual
    machine for Java" (2) to learn more about enabling java class
    sharing in WebShere Application Server.
    References:
    1. WebSphere Application Server Network Deployment 9.0,
    "Tuning the IBM virtual machine for Java".
    https://www.ibm.com/support/knowledgecenter/SSAW57_9.0.0/
    com.ibm.websphere.nd.multiplatform.doc/ae/
    tprf_tunejvm_v61.html
    2. IBM SDK, Java Technology Edition 8.0.0, "Class data
    sharing".
    https://www.ibm.com/support/knowledgecenter/en/SSYKE2_8.0.0/
    com.ibm.java.vm.80.doc/docs/shrc.html
    

Problem conclusion

  • APAR PH12606 enables Java Enterprise Edition application class
    sharing in Application Server, Node Agent, and Deployment
    Manager processes that use the IBM JVM.
    
    The fix for this APAR is currently targeted for inclusion in
    fix pack 9.0.5.0.  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

    PH12606

  • Reported component name

    WEBSPHERE APP S

  • Reported component ID

    5724J0800

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-05-29

  • Closed date

    2019-06-27

  • Last modified date

    2019-06-27

  • 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

    WEBSPHERE APP S

  • Fixed component ID

    5724J0800

Applicable component levels

  • R900 PSY

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"900","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
17 October 2021