IBM Support

IV71556: HIGH CPU USAGE WITH WEBSPHERE MQ DUE TO NON-XATRANSACTIONS NOT BEING RELEASED FROM THE INTERNAL TRANSACTIONTABLE

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • High CPU usage may be reported with WebSphere MQ agents
    processes (amqzlaa0) due to a problem when releasing non-XA
    zombie transactions from the internal transaction table.
    
    A zombie transaction is one that has completed but an
    external reference to the transaction could not be released
    by the application during normal WebSphere MQ syncpoint
    processing.
    The external reference might be caused by runmqsc or other
    monitoring applications that scan the transaction table.
    
     To diagnose this issue do the following at regular intervals.
    
     This documentation captures the increasing non-XA
    transactions. The volume of trace should be monitored to ensure
    that it does not fill the file system.
    
    
     1. amqldmpa -m  -c K -f /var/mqm/errors/kern.txt
     A list of attached connections.
    2. amqldmpa -m  -c A -O2 -f/var/mqm/errors/atm.txt
     A list of the transaction table.
    3. strmqtrc -m  -t detail -p
     where PID= process ID for amqzmuc0
    

Local fix

  • Restart the queue manager to provide temporary workaround
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of WebSphere MQ with utility applications that frequently
    monitor queue manager connections, for example an MQSC script
    which issues DIS CONN(*).
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A build up of ZOMBIE transactions over an extended period within
    MQ's internal transaction table can cause performance issues and
    degradation of queue manager performance. MQ was not releasing
    the ZOMBIE transactions in a timely manner.
    

Problem conclusion

  • WebSphere MQ has been modified to ensure that ZOMBIE
    transactions are correctly released at the earliest appropriate
    moment.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.0       7.0.1.14
    v7.1       7.1.0.8
    v7.5       7.5.0.6
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV71556

  • Reported component name

    WMQ LIN X86 V7

  • Reported component ID

    5724H7224

  • Reported release

    710

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-03-27

  • Closed date

    2015-09-30

  • Last modified date

    2015-09-30

  • 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

    WMQ LIN X86 V7

  • Fixed component ID

    5724H7224

Applicable component levels

  • R710 PSY

       UP

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSFKSJ","label":"WebSphere MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.1"}]

Document Information

Modified date:
09 March 2021