Step 1 Preload CALC Processing

>Preload CALC processing is an optional step that precedes the actual database load.
idms
 
Preload CALC processing is an optional step that precedes the actual database load. Its intent is to improve the performance of load processing and is especially recommended, as follows:
  • There are large amounts of DL/I data.
  • There are logical relationships in the DL/I database.
  • Space requirements need to be determined for the logical workfile(s) that will be generated by the load (Step 2).
2
2
Operation
Preload CALC processing performs the following operations:
  1. Accessing the IPSB load module
  2. Accessing the subschema module named in the IPSB
  3. Reading the DL/I input data
  4. Generating database page numbers for the DL/I root segments
  5. Updating the DL/I data with the database page numbers and writing it out to the DL/I output file
  6. Printing a report on the updated DL/I data
The following diagram shows the operations performed by preload CALC processing.
IDMSDB--Operation
 
To execute the preload CALC processing step, use the JCL in CA IDMS DLI Transparency JCL.
Report
The report produced by the preload CALC processing step lists the following:
  • The DBDNAME for each DL/I database included in the input DL/I data
  • The name and level for each DL/I segment, by database
  • An indication if a segment is a logical child (LC) or logical parent (LP)
  • The number of segment occurrences (records) found, by database
  • The number of logical records found, by database
Following is an example of a report:
     *** CA IDMS/DLI TRANSPARENCY DATABASE LOAD          PROCESS=CALC,IPSB=ITEMPART          DBDNAME=ITEMDBDL          SEGMENT COUNT LEVEL RECORD          ITEM    1086    01  ITEM      LC  DETAIL  3542    02  DETAIL          TOTAL:  4628  RECORDS READ                  3542  LOGICAL RECORDS                     0  LOGICAL RECORDS WRITTEN      *** CALC PROCESSING COMPLETE      ___________________________________________________________________      *** CA IDMS/DLI TRANSPARENCY DATABASE LOAD          PROCESS=CALC,IPSB=ITEMPART          DBDNAME=PARTDBDL          SEGMENT COUNT LEVEL RECORD      LP  PART     789    01  PART          TOTAL:   789  RECORDS READ                   789  LOGICAL RECORDS                      0 LOGICAL RECORDS WRITTEN      *** CALC PROCESSING COMPLETE
Preload Sorting (step 1, part 2)
Use Your Own Sort/Merge Utility
To further optimize the CALC-processed data for loading, you can sort it using your own sort/merge facility. As input to the sort/merge facility, supply the DL/I output file produced by the preload CALC processing. The output file will contain the CALC-processed data in sorted form. You can then use the sorted output file as input to the database load (Step 2).
The preload sort is not strictly required, but it should be performed to produce the most effective ordering of the CALC-processed data.
To perform the preload sort, you must use your own sort/merge facility.
What the Preload Sort Does
The preload sort performs the following operations:
  1. Accessing the CALC DL/I data produced by the preload CALC processing (Step 1, Part1)
  2. Sorting the data so that root segments (CALC records) are in descending database page sequence (the optimum CA IDMS/DB database load order)
To execute the preload sort processing step, use the JCL (Step 1, Part 2) in CA IDMS DLI Transparency JCL.