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IT21338: MQ V9 AMS interceptor does not emulate queue manager blank padding of MQMD format field

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APAR status

  • Closed as program error.

Error description

  • A discrepancy is observed in the handling of null (0x00) bytes
    in the MQMD format field when AMS interception is enabled.
    If an AMS policy is not defined, and the message is not
    protected whilst on the queue, the null bytes in the MQMD format
    field are converted to blank characters (for example, 0x20 in
    ASCII codepages) before being returned to the application during
    If an AMS policy is defined, null byes are not converted, and
    remain present in the MQMD format field returned by MQGET.

Local fix

  • C sender application needs to be modified to set the md.Format
    to "MQFMT_NONE".

Problem summary

  • ****************************************************************
    All uses of native MQ AMS interceptors, which covers users
    running intercepted native applications and users who have
    configured MCA interception on SVRCONN channels.
    All qualities of AMS protection are affected.
    Platforms affected:
    AMS protection is intended to be invisible to the target
    application when the message is consumed. However, when AMS
    protection is applied, the queue manager is unable to blank-pad
    the MQMD format field of the message with space characters, as
    is the expected behaviour. In this case, the blank padding
    should be applied by the AMS interceptor when the message is
    unprotected during MQGET processing, but this logic was not
    present in the native AMS interceptor.

Problem conclusion

  • The native AMS interceptor logic has been updated to blank-pad
    the MQMD format field when the message is unprotected.
    The fix is targeted for delivery in the following PTFs:
    Version    Maintenance Level
    v9.0 LTS
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'

Temporary fix


APAR Information

  • APAR number


  • Reported component name

    IBM MQ AMS V9.0

  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date


  • Closed date


  • Last modified date


  • 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

    IBM MQ AMS V9.0

  • Fixed component ID


Applicable component levels

  • R900 PSY


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Document Information

Modified date:
01 August 2017