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 on AIX , HP-UX, z/OS®, IBM® i, Solaris, Linux , Windows, 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
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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
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Description: Message priority. Data type: MQLONG. Value: - MQPRI_PRIORITY_AS_Q_DEF
- The priority is that of the event queue.
- Persistence
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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
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Description: Type of application that put the message. Data type: MQLONG. Value: - MQAT_QMGR
- Queue manager generated message.
- PutApplName
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Description: Name of application that put the message. Data type: MQCHAR28. Value: The queue manager name at the originating system. - PutDate
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Description: Date when message was put. Data type: MQCHAR8. Value: As generated by the queue manager. - PutTime
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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
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Description: Sequence number of logical message within group. Data type: MQLONG. Value: 1. - Offset
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Description: Offset of data in physical message from start of logical message. Data type: MQLONG. Value: 0. - MsgFlags
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Description: Message flags that specify attributes of the message or control its processing. Data type: MQLONG. Value: MQMF_NONE. - OriginalLength
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Description: Length of original message. Data type: MQLONG. Value: MQOL_UNDEFINED.