Event message MQMD (message descriptor)

The message descriptor for an event message contains information that a system monitoring application can use, such as the message type and format, and the date and time that the message was put on the event queue.

The information in the descriptor informs a system management application that the message type is MQMT_DATAGRAM, and the message format is MQFMT_EVENT.

Many of the fields in an event message contain fixed data, which is supplied by the queue manager that generated the message. The MQMD also specifies the name of the queue manager (truncated to 28 characters) that put the message.

For an event message, the MQMD structure contains the following values:

    StrucId

    Description: Structure identifier.
    Data type: MQCHAR4.
    Value: MQMD_STRUC_ID

    Version

    Description: Structure version number.
    Data type: MQLONG.
    Values:

      MQMD_VERSION_1
      Version-1 message descriptor structure, supported in all environments.

      MQMD_VERSION_2
      Version-2 message descriptor structure, supported in the following environments:

      • AIX
      • IBM i
      • Linux
      • Windows
      • z/OS

      and all IBM MQ MQI clients connected to these systems.

    Report

    Description: Options for report messages.
    Data type: MQLONG.
    Value:

      MQRO_NONE
      No reports required.

    MsgType

    Description: Indicates type of message.
    Data type: MQLONG.
    Value: MQMT_DATAGRAM.

    Expiry

    Description: Message lifetime.
    Data type: MQLONG.
    Value:

      MQEI_UNLIMITED
      The message does not have an expiry time.

    Feedback

    Description: Feedback or reason code.
    Data type: MQLONG.
    Value: MQFB_NONE.

    Encoding

    Description: Numeric encoding of message data.
    Data type: MQLONG.
    Value: MQENC_NATIVE.

    CodedCharSetId

    Description: Character set identifier of event message data.
    Data type: MQLONG.
    Value: Coded character set ID (CCSID) of the queue manager generating the event.

    Format

    Description: Format name of message data.
    Data type: MQCHAR8.
    Value:

      MQFMT_EVENT
      Event message.

    Priority

    Description: Message priority.
    Data type: MQLONG.
    Value:

      MQPRI_PRIORITY_AS_Q_DEF
      The priority is that of the event queue.

    Persistence

    Description: Message persistence.
    Data type: MQLONG.
    Value:

      MQPER_PERSISTENCE_AS_Q_DEF
      The priority is that of the event queue.

    MsgId

    Description: Message identifier.
    Data type: MQBYTE24.
    Value: A unique value generated by the queue manager.

    CorrelId

    Description: Correlation identifier.
    Data type: MQBYTE24.
    Value: For performance, queue manager, logger, channel, bridge, and SSL events:

      MQCI_NONE
      No correlation identifier is specified. This is for private queues only.

      For such events on a shared queue, a nonzero correlation identifier is set. This parameter is set so that we can track multiple event messages from different queue managers. The characters are specified in the following way:

      1-4 Product identifier ('CSQ ')

      5-8 Queue sharing group name

      9 Queue manager identifier

      10-17 Time stamp

      18-24 Nulls

      For configuration and command events:

      A unique nonzero correlation identifier
      All messages relating to the same event have the same CorrelId.

    BackoutCount

    Description: Backout counter.
    Data type: MQLONG.
    Value: 0.

    ReplyToQ

    Description: Name of reply queue.
    Data type: MQCHAR48.
    Values: Blank.

    ReplyToQMgr

    Description: Name of reply queue manager.
    Data type: MQCHAR48.
    Value: The queue manager name at the originating system.

    UserIdentifier

    Description: Identifies the application that originated the message.
    Data type: MQCHAR12.
    Value: Blank.

    AccountingToken

    Description: Accounting token that allows an application to charge for work done as a result of the message.
    Data type: MQBYTE32.
    Value: MQACT_NONE.

    ApplIdentityData

    Description: Application data relating to identity.
    Data type: MQCHAR32.
    Values: Blank.

    PutApplType

    Description: Type of application that put the message.
    Data type: MQLONG.
    Value:

      MQAT_QMGR
      Queue manager generated message.

    PutApplName

    Description: Name of application that put the message.
    Data type: MQCHAR28.
    Value: The queue manager name at the originating system.

    PutDate

    Description: Date when message was put.
    Data type: MQCHAR8.
    Value: As generated by the queue manager.

    PutTime

    Description: Time when message was put.
    Data type: MQCHAR8.
    Value: As generated by the queue manager.

    ApplOriginData

    Description: Application data relating to origin.
    Data type: MQCHAR4.
    Value: Blank.

Note: If Version is MQMD_VERSION_2, the following additional fields are present:

    GroupId

    Description: Identifies to which message group or logical message the physical message belongs.
    Data type: MQBYTE24.
    Value:

      MQGI_NONE
      No group identifier specified.

    MsgSeqNumber

    Description: Sequence number of logical message within group.
    Data type: MQLONG.
    Value: 1.

    Offset

    Description: Offset of data in physical message from start of logical message.
    Data type: MQLONG.
    Value: 0.

    MsgFlags

    Description: Message flags that specify attributes of the message or control its processing.
    Data type: MQLONG.
    Value: MQMF_NONE.

    OriginalLength

    Description: Length of original message.
    Data type: MQLONG.
    Value: MQOL_UNDEFINED.

Parent topic: Event message reference