IBM SC34-7012-01 manual Exec Cics Cancel requests, Basic mapping support BMS messages

Table 1. Effect of RESTART option on started transactions (continued)

Description of	Events	Effect of	Effect of
non-terminal START		RESTART(YES)	RESTART(NO)
command
Specifies nonrecoverable	Started task	Transaction is restarted	START request
data	abends without	with its data still	and its data are
	retrieving its data	available, up to n¹	discarded.
		times.
Without data	Started task	Transaction is restarted	—
	abends	up to n¹ times.

¹n is defined in the transaction restart program, DFHREST, where the CICS-supplied default is 20.

EXEC CICS CANCEL requests

Recovery from CANCEL requests during transaction backout depends on whether the data is being passed to the started task and if the temporary storage queue used to pass the data is defined as recoverable.

During transaction backout of a failed task that has canceled a START request that has recoverable data associated with it, CICS recovers both the temporary storage queue and the start request. Thus the effect of the recovery is as if the CANCEL command had never been issued.

If there is no data associated with the START command, or if the temporary storage queue is not recoverable, neither the canceled started task nor its data is recovered, and it stays canceled.

Basic mapping support (BMS) messages

Recovery of BMS messages affects those BMS operations that store data on temporary storage.

They are:

vBMS commands that specify the PAGING operand

vThe BMS ROUTE command

vThe message switching transaction (CMSG)

Backout of these BMS operations is based on backing out START requests because, internally, BMS uses the START mechanism to implement the operations listed above. You request backout of these operations by making the BMS temporary storage queues recoverable, by defining their DATAIDs in the temporary storage table. For more information about the temporary storage table, see the CICS Resource Definition Guide.

Application programmers can override the default temporary storage DATAIDs by specifying the following operands:

vREQID operand in the SEND MAP command

vREQID operand in the SEND TEXT command

vREQID operand in the ROUTE command

vPROTECT operand in the CMSG transaction

Note: If backout fails, CICS does not try to restart regardless of the setting of the restart program.

78CICS TS for z/OS 4.1: Recovery and Restart Guide