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IT06500: STEADY SHARED MEMORY GROWTH AFTER THE UPGRADE TO MQ 8.0

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APAR status

  • Closed as program error.

Error description

  • A steady shared memory growth is observed after the upgrade to
    MQ 8.0 until queue manager runs out of shared memory.
    The excessive number of channel status entries is observed as
    well in the core file. The ps output likely to show high memory
    usage
    for the channel processes runmqchl, amqrmppa, runmqchi etc.
    
    FDCs indicating failure in allocating shared memory for channel
    status entry(rriAddStatusEntry)
    might also be generated.
    
    Probe Id :- XY132002
    Component :- xstCreateExtent
    Major Errorcode :- xecP_E_NO_RESOURCE
    Probe Type :- MSGAMQ6024
    Probe Description :- AMQ6024: Insufficient resources are
    available to complete a system request.
    Arith1 :- 18446744073709551615 (0xffffffffffffffff)
    Arith2 :- 22 (0x16)
    Comment1 :- Failed to get memory segment: shmget(0x00000000,
    24576) [rc=-1 errno=22] Invalid argument
    Comment2 :- Invalid argument
    Comment3 :- Configure kernel (for example, shmmax) to allow a
    shared memory segment of at least 24576 bytes
    
    MQM Function Stack
    ccxResponder
    rrxResponder
    rriAcceptSess
    rriAcceptSessReceive
    rriAddStatusEntry
    xcsAllocateHashCell
    xcsAllocateQuickCell
    xstQuickCellExtendBlock
    xcsAllocateMemBlock
    xstExtendSet
    xstCreateExtent
    xcsFFST
    

Local fix

  • Restart the queue manager to release shared memory
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users using MQ client channels with channels starting and ending
    often likely to be affected by this problem.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The queue manager allocates channel status entry for each
    channel instance when the channel is started and frees the entry
    when the channel ends. However the shared memory allocated for
    the channel status entry was not released correctly when freeing
    the channel status entry.
    

Problem conclusion

  • MQ has been modified to correctly release the shared memory
    associated with the channel status entry when freeing the
    channel status entry.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.2
    
    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

    IT06500

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2015-01-14

  • Closed date

    2015-01-27

  • Last modified date

    2015-07-29

  • 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

    5724H7251

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
29 July 2015