IBM Support

PM27960: WLM Compressor Fix and Enhancements

Fixes are available

6.1.0.37: Java SDK 1.5 SR12 FP3 Cumulative Fix for WebSphere
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
6.1.0.47: WebSphere Application Server V6.1 Fix Pack 47
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
6.1.0.39: Java SDK 1.5 SR12 FP4 Cumulative Fix for WebSphere Application Server
6.1.0.41: Java SDK 1.5 SR12 FP5 Cumulative Fix for WebSphere Application Server
6.1.0.43: Java SDK 1.5 SR13 Cumulative Fix for WebSphere Application Server
6.1.0.45: Java SDK 1.5 SR14 Cumulative Fix for WebSphere Application Server
6.1.0.47: Java SDK 1.5 SR16 Cumulative Fix for WebSphere Application Server
7.0.0.19: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
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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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • This APAR contains a fix to optimize how the workload
    management (WLM) component will compress and decompress data
    being sent betweenprocesses. This is designed to reduce
    compression overhead in large WebSphere Process Server or
    service integration bus (SIBus) topologies, specifically with
    a large number of destinations (more effective at 2,000 or more
    destinations). It addresses scenarios in which many clusters
    have been defined and one or more non-messaging engine (ME)
    clusters are restarted while the messaging engine cluster is
    running. A customer experiencing this may see the following:
    
    ThreadMonitor W   WSVR0605W: Thread
    "server.startup : 0" (00000038) has been active for 686179
    milliseconds and may be hung.  There is/are 1 thread(s) in total
    in the server that may be hung.
    at java.lang.Object.wait(Native Method)
    at java.lang.Object.wait(Object.java:199)
    at
    com.ibm.ws.sib.jfapchannel.impl.ExchangeReceiveListener.waitToCo
    mplete(ExchangeReceiveListener.java:235)
    
    In addition this fixes a rare condition which could result in
    compressed data being lost.  This would only occur if a series
    of bytes to be compressed could not actually be compressed
    (every byte was unique). This would then cause a potential loss
    of data due to how WLM handled the uncompressed bytes.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  IBM WebSphere Process Server users or users *
    *                  of IBM WebSphere Application Server with    *
    *                  service integration bus (SIBus)             *
    *                  configurations.                             *
    ****************************************************************
    * PROBLEM DESCRIPTION: Workload management (WLM) Compressor    *
    *                      Fix and Enhancements                    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    In scenarios in which many clusters have been defined
    and one or more non-ME clusters are restarted while the
    messaging engine cluster is running, a customer experiencing
    this may see the following:
    
    ThreadMonitor W   WSVR0605W: Thread
    "server.startup : 0" (00000038) has been active for 686179
    milliseconds and may be hung.  There is/are 1 thread(s) in total
    in the server that may be hung.
    at java.lang.Object.wait(Native Method)
    at java.lang.Object.wait(Object.java:199)
    at
    com.ibm.ws.sib.jfapchannel.impl.ExchangeReceiveListener.waitToCo
    mplete(ExchangeReceiveListener.java:235)
    

Problem conclusion

  • This APAR contains a fix to optimize how the WLM component
    will compress and decompress data being sent between
    processes. This is designed to reduce compression overhead in
    large WPS/SIB topologies, specifically with a large number of
    destinations (more effective at 2,000 or more destinations).
    
    In addition this fixes a rare condition which could result in
    compressed data being lost.  This would only occur if a series
    of bytes to be compressed could not actually be compressed
    (every byte was unique). This would then cause a potential loss
    of data due to how WLM handled the uncompressed bytes.
    
    Although it is not recommended, the compression optimizations
    can be removed and the code reverted back to the prior code if
    problems are seen by setting a cell level custom property:
    
    In the administrative console, go to the Custom properties
    page for the cell.
    
    System administration > Cell >  cell_name, and then, under
    Additional Properties, click Custom Properties
    
    Create a new custom property with a name of:
    
    IBM_CLUSTER_USE_LEGACY_COMPRESSOR
    
    and a value of true.  Save, Synchronize the nodes and restart
    all of the processes in the cell to pick up this change.
    
    The fix for this APAR is currently targeted for inclusion in
    fix packs 6.1.0.37 and 7.0.0.17.  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

    PM27960

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    61I

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-12-01

  • Closed date

    2011-03-02

  • Last modified date

    2011-03-02

  • 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

  • R61A PSY

       UP

  • R61H PSY

       UP

  • R61I PSY

       UP

  • R61P PSY

       UP

  • R61S PSY

       UP

  • R61W PSY

       UP

  • R61Z PSY

       UP

  • R700 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 6.1

Reference #: PM27960

Modified date: 02 March 2011