Managing MsgId and CorrelId in a unit of work

The following diagrams summarize the values that you should use and expect in key fields in the MQMD and MQCIH in typical CICS DPL bridge and CICS 3270 bridge applications.

In Figure 16, running more than one user program using the DPL bridge, the MsgId of the request message is set by the queue manager (to M1), and subsequently copied to the CorrelId. Figure 17 shows a conversational 3270 transaction.

Figure 16. Setting of key fields for many CICS user programs in a unit of work

Setting of key fields for many CICS user programs in a unit of work using the DPL bridge The diagram shows the interaction between a WebSphere MQ application and the CICS bridge: Application request message 1 UOWControl=MQCUOWC_FIRST CorrelId=MQCI_NEW_SESSION Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M1 Application request message 2 UOWControl=MQCUOWC_MIDDLE CorrelId=M1 MsgId=MQMI_NONE Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M2 Application request message 3 UOWControl=MQCUOWC_LAST CorrelId=M1 MsgId=MQMI_NONE Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M3

Figure 17. Setting of key fields: WebSphere MQ - conversational 3270 transaction

Setting of key fields: WebSphere MQ - conversational 3270 transaction The diagram shows the interaction between a WebSphere MQ application and the CICS bridge: Application request message 1 (receive request) UOWControl=MQCUOWC_ONLY ConversationalTask=MQCCT_YES CorrelId=MQCI_NEW_SESSION MsgId=MQMI_NONE Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M1 Application request message 2 (receive request) UOWControl=MQCUOWC_CONTINUE CorrelId=M1 MsgId=MQMI_NONE Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M2 Application request message 3 (receive request) UOWControl=MQCUOWC_CONTINUE CorrelId=M1 MsgId=MQMI_NONE Application does MQGET MsgId=M1 Values set by bridge are: MsgId=M1 CorrelId=M3