How to know the name of program mirror transaction in CICS?

Customer Information Control System. Middleware and MQ Series.
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Anup Apte
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How to know the name of program mirror transaction in CICS?

Post by Anup Apte »

Hi,

My knowledge about mirror transactions is very less in CICS, does mirror transactions also have the similar entries like we have in PCT for usual setup in CICS. If it is not that way, how to know the name of program mirror transaction in CICS? Please help.
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Robert Sample
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Re: How to know the name of program mirror transaction in CICS?

Post by Robert Sample »

Have you looked at the manuals for your release of CICS? The CICS TS 5.1 Reference manual says:
When a transaction issues a command for a function to run on a remote system, the local CICS system encodes the request and sends it to the remote system. The remote system attaches one of the CICS-supplied mirror transactions, which all use the mirror program, DFHMIRS.

The CVMI and CPMI mirror transactions service requests sent as part of an LU6.2 synclevel 1 conversation. The CPMI, CSMI, CSM1, CSM2, CSM3, and CSM5 mirror transactions service requests that are sent as part of an LU6.2 synclevel 2 conversation, an LU6.1 conversation, an MRO conversation, or an IPIC conversation.

For distributed program link (DPL) requests shipped from a CICS application region to a CICS resource region, you can specify the name of the mirror transaction to be attached. If you specify your own mirror transaction, you must define the transaction in the resource region and associate it with the CICS-supplied mirror program, DFHMIRS.

A mirror transaction runs the request from the initiating transaction and returns to the local system the response code and any control fields and data that are associated with the request. If running the request causes the mirror transaction to abend, this information is also returned to the initiating transaction.

If a resource has browse place holders or is recoverable, or the lock has been acquired, the mirror transaction becomes a long-running mirror and does not end until the issuing transaction ends the logical unit of work; that is, a SYCNPOINT or RETURN. Any resources that the mirror has acquired are freed when the initiating transaction issues the appropriate command to free those resources.

The CICS-supplied mirror program DFHMIRS is defined as a threadsafe program. For IPIC connections only, CICS runs DFHMIRS on an L8 open TCB whenever possible. For other connection types, CICS does not run DFHMIRS on an open TCB. For threadsafe applications that issue commands for functions on remote CICS systems over IPIC connections, the reduction in TCB switching improves application performance compared to other intercommunication methods. For file control commands, to gain the performance improvement, you must specify the system initialization parameter FCQRONLY=NO in the file-owning region.
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