DRA control exit (DFHDBCTX)

This exit is invoked by the DRA, when connection has been established with the DBCTL address space, to initiate the resynchronization process, that is, to initiate the resolution of indoubt units of work. It is also invoked to handle cases where connection to DBCTL cannot be achieved or when the connection has failed.

The control exit is invoked in the DRA environment in the following circumstances:

When contact has been established with the DBCTL address space, in order to initiate resynchronization.
The control exit is invoked in the DRA environment whenever contact has been established with DBCTL, whether invoked by the user or due to the DRA automatically reestablishing contact after a DBCTL failure. The control exit receives an input parameter list that includes the DBCTL ID, DBCTL’s list of indoubt units of work, and the DBCTL RSE name. The control exit posts the control program, which performs the resynchronization.
When the MVS subsystem interface (SSI) rejects the IDENTIFY request to DBCTL, thereby causing the IDENTIFY to fail.
This could occur if the DRA was trying to issue an IDENTIFY request to a DBCTL subsystem that was not running. In this case the control exit sets a response code of ‘0’. The first time in a connection attempt that the DRA receives a ‘0’ response after an MVS SSI failure, the DRA outputs message DFS690A inviting the operator to reply WAIT or CANCEL. On subsequent failures when a response code of ‘0’ is returned, the DRA waits for the length of time specified in the DRA startup table before attempting the IDENTIFY request again.
When DBCTL rejects the IDENTIFY request to DBCTL; for example, incorrect application group name (AGN) supplied.
In this case, the control exit asks the DRA to terminate.
When the operator replies CANCEL to the DFS690A message during DRA initialization, because contact cannot be established with DBCTL.
In this case, the control exit notifies the DRA to terminate immediately.
When DBCTL abnormally terminates.
In this case, the control exit invokes the control program and then it asks the DRA to issue an IDENTIFY request to DBCTL.
When the DRA abnormally terminates.
In this case, it is not possible to access DBCTL from the same CICS® session without initializing the CICS-DBCTL interface using the menu program.
When a /CHECKPOINT FREEZE request has been issued to DBCTL.
Note that /CHECKPOINT FREEZE is the command used to close down a DBCTL subsystem. In this case the control exit invokes the control program which, in turn, invokes the disconnection program requesting an orderly disconnection from DBCTL. The control exit notifies the DRA to wait for a termination request.