One of the most common questions when using REORG, is how to estimate the Work File dataset sizes. Within CA IDMS REORG setup execution options, there's syntax " ESTIMATE workfile sizes" that estimates the size of all work files after UNLOADing the data. Or alternatively you can execute this statement as a separate job to get this report.
CREATE DSMODEL W*
REORG SEGMENT APPLDICT USING IDMSNWKU
RELOAD INTO APPLDICT USING IDMSNWKU DMCL RELD1600
DIVIDE PROCESSING 4 WAYS
ESTIMATE WORKFILE SIZES SUBMIT
STOP AFTER UNLOAD
CREATE ALL WORKFILES
Please see the IDMS 17.0 SP1 Release Summary, page 274 7.12 REORG Enhancements
Syntax for REORG ESTIMATE workfile sizes
and also Chapter 126.96.36.199 Work Files
"Work file creation: REORG can create work files dynamically, or you can
manually create them prior to beginning the UNLOAD and/or RELOAD phases
of REORG execution. Regardless of how the files are created, it is a good idea
to halt execution after setup to determine what work files are needed by
examining the report produced by REORG
If using dynamic work file creation, you must specify the attributes of the work
files using one or more CREATE DSMODEL statements. REORG creates the
files as directed by the CREATE WORKFILE clause or at the time they are first
accessed. Dynamically created work files, other than DBKEYS files, are deleted
automatically during the cleanup phase.
If you want to use REORG's size estimates to create a file, code a DSMODEL
without a primary SPACE allocation. You can code a SPACE parameter with
just a unit type (TRK, CYL, or blksize) and no value for primary allocation."
Example of the REORG Task and Work File Usage report is in the REORG Status Report –Section 5:
TEC427060 How to get started on the first execution of the new REORG utility to expand a database area.
TEC4820704 CREATE DSMODEL statement in REORG for sort work datasets.
TEC587833 Specifying space for REORG work files, to avoid a B37, D37, E37 abend.