Table 1. Effect of RESTART option on started transactions (continued)
Description of
non-terminal START
command
Events Effect of
RESTART(YES)
Effect of
RESTART(NO)
Specifies nonrecoverable
data
Started task
abends without
retrieving its data
Transaction is restarted
with its data still
available, up to n¹
times.
START request
and its data are
discarded.
Without data Started task
abends
Transaction is restarted
up to n¹ times.
—
¹ n is defined in the transaction restart program, DFHREST, where the
CICS-supplied default is 20.
Note: Channel data is not recoverable, therefore channels are not available on
restart. Transactions with large channels, for example, greater than 32 KB, cannot
be restarted.
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:
v BMS commands that specify the PAGING operand
v The BMS ROUTE command
v The 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:
v REQID operand in the SEND MAP command
v REQID operand in the SEND TEXT command
v REQID operand in the ROUTE command
78 CICS TS for z/OS 4.1: Recovery and Restart Guide
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