Filter
Top Products
DFH$FCBV sample global user exit program
DFH$FCBV provides sample processing for the file control backout override global
user exit, XFCBOVER. The exit program, if enabled at the XFCBOVER exit point, is
invoked when a log record is presented to file control for backing out an update to a
data set in RLS access mode, after the data set has been used in a batch update
despite the existence of retained locks. A consequence of running a batch program
while there are retained locks is that a lock that protected a record updated by
CICS could have been overridden by a non-RLS batch program.
There is more information about using the XFCBOVER exit, and about the
DFH$FCBV sample program, in the comments within the DFH$FCBV source code.
The comments also include some suggested extensions that you can make to the
sample program to reflect the pattern of batch usage at your installation.
In summary, DFH$FCBV performs the following processing:
v Makes a user trace entry if tracing is active for file control. This has trace point id
X'01E0' and traces:
– An eye-catcher ‘DFH$FCBV ENTRY’
– The data set name
– The file control portion of the log record.
v Checks the data set name to see if it is one of those for which it is known that
batch programs never update existing records, but only insert new records, or do
not make updates at all. The sample program contains a table of such data sets.
If this data set is in the table, UERCBCKO is returned. UERCBCKO means that
CICS is to perform the backout, despite the override option having been used,
because the locked record cannot have been updated by a batch job.
v For all other data sets, it must be assumed that the batch job could have
updated the record being backed out. The sample therefore returns
UERCNORM, which instructs CICS to take the default action of not backing out
the update.
v Exit from the program, making:
– A user trace entry if tracing is active for file control. This has trace point id
X'01E1' and traces:
- An eye-catcher ‘DFH$FCBV EXIT’
- The data set name
- Some text: ‘Update will be backed out’, or ‘Update will not be backed out’
as appropriate.
file control recovery program exits
Chapter 1. Global user exit programs 121