102 ICF Catalog Backup and Recovery: A Practical Guide
6.7 MERGECAT command
The Catalog RecoveryPlus MERGECAT command provides functions that are
similar to the IDCAMS REPRO MERGECAT and NOMERGECAT commands. It
moves or copies records from one BCS to another, allowing you to merge,
split, or clone BCS records.
In general, the MERGECAT command can be used to move all or some BCS
records to another BCS. Depending on the keywords that you code with this
command, aliases may be changed from the input BCS to the output BCS.
not using the COPYONLY keyword, the MERGECAT command performs
as a move function, and therefore, VVDS records for all data sets whose catalog
entry is moved will have a BCS back-pointer update. To achieve maximum
performance in this operation, the BCS back-pointer updates are saved until the
end of processing and are then performed a volume at a time, so that all updates
to each VVDS are done at once. This is unlike the logic in IDCAMS REPRO
MERGECAT, where the VVDS updates are done at the time each record is
moved from the source to the target BCS. This logic is one of the primary factors
in the performance obtained by the CR+ MERGECAT command.
Figure 6-32 illustrates the command used for moving
records in a BCS to
another BCS.
Figure 6-32 MERGECAT command to move all BCS records
Every catalog record in UCAT.CRPLUS3 is moved to UCAT.CRPLUS5, and every
alias for UCAT.CRPLUS3 in the master catalog is moved to UCAT.CRPLUS5. At
completion of this command, UCAT.CRPLUS3 is an empty catalog. For every
data set whose catalog record is moved, all the VVDS records (VVRs and NVRs)
change their BCS back-pointer value from UCAT.CRPLUS3 to UCAT.CRPLUS5.
In Figure 6-33, you see the command used to move all records with a high-level
qualifier of YCJRES3, from user catalog UCAT.CRPLUS3 to UCAT.CRPLUS5. By
using the level keyword, the alias YCJRES3 is also changed in the master
catalog from its relationship to UCAT.CRPLUS3 to UCAT.CRPLUS5.

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