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CICS recovers after a cache failure automatically. There is no need for manual
intervention (other than the prerequisite action of resolving the underlying cause of
the cache failure).
Lost locks recovery
The failure of a coupling facility lock structure that cannot be rebuilt by VSAM
creates the lost locks condition.
The lost locks condition can occur only for data sets opened in RLS mode. A data
set can be made available for general use only after all the CICS regions that were
accessing the data set at the time of the lock structure failure have completed the
process known as lost locks recovery.
Issue the IDCAMS SHCDS LISTUBSYS(ALL) command to display the lost locks and
the owners of those locks.
Rebuilding the lock structure
When a coupling facility lock structure fails, the SMSVSAM servers attempt to
rebuild their locks in the lock structure from their own locally-held copies of the
locks. If this is successful, the failure is transparent to CICS.
About this task
If the rebuild fails, all SMSVSAM servers abend and restart, but they are not
available for service until they can successfully connect to a new coupling facility
lock structure. Thus a lock structure failure is initially detected by CICS as an
SMSVSAM server failure, and CICS issues message DFHFC0153.
When the SMSVSAM servers abend because of this failure, the sharing control data
set is updated to reflect the lost locks condition. The sharing control data set
records:
v The data sets whose locks have been lost.
v The CICS regions that must complete lost locks recovery for each data set. These
are the CICS regions that had a data set open for update (in RLS-mode) for
which the locks have been lost.
Notifying CICS of SMSVSAM restart
When the SMSVSAM servers are able to connect to a new lock structure, they use
the MVS ENF to notify the CICS regions that their SMSVSAM server is available
again.
CICS is informed during dynamic RLS restart about those data sets for which it
must perform lost locks recovery. CICS issues a message (DFHFC0555) to inform
you that lost locks recovery is to be performed for one or more data sets.
If a lost-locks condition occurs and is not resolved when a CICS restart (warm or
emergency) occurs, CICS is notified during file control restart about any data sets
for which it must perform lost locks recovery. On a cold start, CICS does not
perform any lost locks recovery, and the information in the sharing control data
set, which records that CICS must complete lost locks recovery, is cleared for each
data set. This does not affect the information recorded for other CICS regions.
Only units of work performing lost locks recovery can use data sets affected by
lost locks. Error responses are returned on open requests issued by any CICS
Chapter 8. Unit of work recovery and abend processing 89