Executing Batch Backout While RCDS are Unavailable
Some terminology
- Batch Backout is a CICS VR function that removes all changes made to a particular VSAM data set by a specific batch job or a step in a batch job.
- Recovery Control data set (RCDS) are VSAM data sets that are a repository of the necessary information to create the job to recover VSAM data sets.
Changes needed to handle the situation
- The batch job updates the recovered data through the RCDS which was allocated to CICS VR server address space
- To backout the VSAM dataset, CICS VR batch backout job runs to retrieve the data from RCDS through DWWCONx DD statements.
We might encounter a situation where the RCDS are no longer available. In that case, we can execute Batch Backout by using the name of the MVS log (undo log stream as CVRTEST.UNDOLOG).
To run CICS VR batch backout when the RCDS are unavailable, complete the following additional tasks:
- Remove the DWWCONx DD statements from the batch backout JCL.
- Add the RCDS (NO) keyword to the BATCHBACK command. RCDS (NO) indicates that the RCDS are unavailable to CICS VR during this batch backout run.
- Add the MVSLOG (undo log stream) command to the batch backout job. Undo log stream is the name of the undo log stream that was defined to CICS VR, when the batch job that made the updates that want to back out was originally run.
Note: Specify the MVSLOG (undo log stream as CVRTEST.UNDOLOG) command to the batch backout job instead of RCDS.
Report of Batch backout data sets statistics
CICSVR - BATCH BACKOUT UTILITY
BATCH BACKOUT JOB STEP STATISTICS:
----------------------------------
KEY TO FIELD IDENTIFIERS
-----------------------------------------------------------------
NO OF UNDOS FOR STEP - NUMBER OF UNDO RECORDS ENCOUNTERED FOR STEP
NO OF DATA SETS - DIFFERENT DATA SETS UPDATED
UPD-BEFORE - DELETE OR UPDATE BEFORE IMAGE
ADD-BEFORE - ADD BEFORE IMAGE
ADDS - NUMBER OF ADDED RECORDS
UPDATES - NUMBER OF UPDATED RECORDS
DELETES - NUMBER OF DELETED RECORDS
-----------------------------------------------------------------
JOB NAME: LOAD2
JOB ID: JOB02710
NAME OF LOGSTREAM:
CVRTEST.UNDOLOG
JOB STEP -NO OF - -NO OF - -- NUMBER OF BEFORE-- ---- NUMBER OF CHANGED ----- CHANGES
NAME UNDOs DATA IMAGE LOG RECORDS VSAM RECORDS IGNORED
FOR STEP SETS UPD-BEFORE ADD-BEFORE ADDS UPDATES DELETES BY EXIT
-------- -------- -------- ---------- ---------- --------- -------- -------- --------
ADDREC2 4 1 0 4 0 0 4 0
-------- - ------- -------- ---------- ---------- -------- -------- -------- --------
LOAD2 5 1 0 5 0 0 5 0
-------- -------- -------- ---------- ---------- --------- -------- -------- --------
TOTAL 9 2 0 9 0 0 9 0
-------- -------- -------- ---------- ---------- --------- -------- -------- --------
1CICSVR - BATCH BACKOUT UTILITY DATE : 21/05/19 TIME : 19:54:01 PAGE : 2
0
BATCH BACKOUT DATA SET STATISTICS
---------------------------------
JOB NAME: LOAD2
JOB ID: JOB02710
BASE NAME OF BACKED OUT DATA SET: CVTEST3.BLOG.KSDS1
BASE NAME OF ORIGINAL DATA SET: CVTEST3.BLOG.KSDS1
FIRST AND LAST LOG RECORDS APPLIED:
DATE TIME TIME
RECORDS YYYY.MM.DD HH:MM:SS TYPE
-------------------------------------- ---------- -------- -----
LOG BLOCK TIME STAMP AT BACKOUT START 2021.05.19 19:51:24 LOCAL
LOG BLOCK TIME STAMP AT BACKOUT END 2021.05.19 19:51:21 LOCAL
-------------------------------------- ---------- -------- -----
JOB STEP ----- NUMBER OF BEFORE --- ------- NUMBER OF CHANGED ------ CHANGES
NAME IMAGE LOG RECORDS VSAM RECORDS IGNORED
UPD-BEFORE ADD-BEFORE ADDS UPDATES DELETES BY EXIT
-------- ----------- ------------ --------- ---------- --------- -----------
ADDREC2 0 4 0 0 4 0
-------- ----------- ------------ --------- ---------- --------- -----------
LOAD2 0 5 0 0 5 0
-------- ----------- ------------ --------- ---------- --------- -----------
TOTAL 0 9 0 0 9 0
-------- ----------- ------------ --------- ---------- --------- -----------
- ------- ----------- ------------ --------- ---------- --------- -----------
OVERALL
TOTAL 0 9 0 0 9 0
-------- ----------- ------------ --------- ---------- --------- -----------
BATCH BACKOUT EXIT ACTION STATISTICS
------------------------------------
JOB NAME: LOAD2
JOB ID: JOB02710
:---------NUMBER OF -----------:
EXIT NAME RECORDS PASSED TO THE EXIT
------------------ ------------------------------
ESDS DELETE 0
------------------ ------------------------------
This batch backout data set statistics report contains information about the type of updates that superscript were backed out from each VSAM data set.
Drawback :
Executing CICS VR batch backout without the RCDS allocated causes,
- Loss of Efficiency
- Increased Processing Time
- Less Error Checking
That is why RCDS is used by CICS VR batch backout to perform various error checking and improve performance.
Contact :
Dionne A Nerissa
QA Engineer – CICS VR