IBM Support

IT15112: MQ channel agent pool process (amqrmppa) memory usage increases over time

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • While running MQ 7.5.0.5, the amqrmppa process memory usage
    increases up to 2GB over the course of a day. Over a week,
    the amqrmppa process memory usage increases up to 10GB.
    

Local fix

  • The following workarounds may help remedy the issue, they are
    listed in order that will have the least impact on a
    production system:
    .
    1) Disable FASTPATH channels by removing the
        MQIBindType=FASTPATH entry in qm.ini
       .
       Disabling FASTPATH channels will cause a small dip in overall
       performance but this may be a reasonable trade-off for
    stability.
    
    2) Stop using the -x option on strmqm
       .
       The other option is to stop using the -x option on strmqm if
       the production environment can afford to be without the
       multi-instance functionality for a period.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of multi-instance queue managers may be affected by this
    issue.  If FASTPATH channels and managed subscriptions are being
    used then the possibility of being affected increases.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    IBM MQ maintains an internal process-wide file handle cache
    which can grow dynamically.  When multi-instance queue managers
    were being used, a coding error introduced a window where memory
    used to grow this cache could be leaked between instances of IBM
    MQ threads.
    

Problem conclusion

  • The MQ queue manager code was modified so that the cache space
    allocated by a thread is freed if no other threads are using the
    process-wide file handle cache.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.5       7.5.0.8
    v8.0       8.0.0.6
    v9.0 CD    9.0.1
    v9.0 LTS   9.0.0.1
    
    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

    IT15112

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7241

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-05-05

  • Closed date

    2016-07-28

  • Last modified date

    2017-06-01

  • 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 BASE MULTIP

  • Fixed component ID

    5724H7241

Applicable component levels

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSCPQ63","label":"APAR \/ Maintenance"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.5","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
01 June 2017