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performs the recovery process for work that was in-flight when the previous run of
CICS was abnormally terminated.
Recovery of data during an emergency restart
During the final stage of emergency restart, the recovery manager uses the system
log data to drive backout processing for any units of work that were in-flight at
the time of the failure. The backout of units of work during emergency restart is
the same as a dynamic backout; there is no distinction between the backout that
takes place at emergency restart and that which takes place at any other time.
The recovery manager also drives:
v The backout processing for any units of work that were in a backout-failed state
at the time of the CICS failure.
v The commit processing for any units of work that were in a commit-failed state
at the time of the CICS failure.
v The commit processing for units of work that had not completed commit at the
time of failure (resource definition recovery, for example).
The recovery manager drives these backout and commit processes because the
condition that caused them to fail may be resolved by the time CICS restarts. If the
condition that caused a failure has not been resolved, the unit of work remains in
backout- or commit-failed state. See “Backout-failed recovery” on page 79 and
“Commit-failed recovery” on page 83 for more information.
For more information about the emergency restart process, see Chapter 6, “CICS
emergency restart,” on page 61.
Cold start
On a cold start, CICS reconstructs the state of the region from the previous run for
remote resources only. For all resources, the region is built from resource
definitions specified on the GRPLIST system initialization parameter and those
resources defined in control tables.
The following is a summary of how CICS uses information stored in the global
catalog and the system log on a cold start:
v CICS preserves, in both the global catalog and the system log, all the
information relating to distributed units of work for partners linked by:
– APPC
– MRO connections to regions running under CICS Transaction Server
– The resource manager interface (RMI); for example, to DB2 and DBCTL.
v CICS does not preserve any information in the global catalog or the system log
that relates to local units of work.
Generally, to perform a cold start you specify START=COLD, but CICS can also
force a cold start in some circumstances when START=AUTO is specified. See the
CICS System Definition Guide for details of the effect of the START parameter in
conjunction with various states of the global catalog and the system log.
An initial start of CICS
If you want to initialize a CICS region without reference to the global catalog from
a previous run, perform an initial start.
36 CICS TS for z/OS 4.1: Recovery and Restart Guide