MERGE and DSNTYPE=LARGE for ML1 allocated files
Article ID: 386381
Updated On:
Products
Issue/Introduction
During MERGE processing, intermediate files for the MERGE are allocated with a maximum of 65,535 Tracks , thus causing an allocation of "small" extents and expanding to many volumes . When a secondary space is needed , only half of that tracks quantity is allocated . In the end , such a process can abend with SB37-04 because all volumes in the ML1 pool are space exhausted .
The question is whether DISK supports allocating ML1 files with DSNTYPE=LARGE parameter and if so , where this change should be implemented . Also if it is possible to increase the secondary space allocation of these files.
Environment
All
Resolution
Regarding the intermediate files allocated and used by MERGE procedure (ML1 files ) , they are currently allocated at program level with a maximum Primary space of 65,535 Tracks . Subsequent allocations are with 32,973 tracks , residing on additional 15 volsers for a total of 16 extents . At this time DSNTYPE=LARGE is not supported.
Additional Information
Regarding the MERGE procedure files allocated as //DSNIIN DD and //DSNIOUT DD :
due to the current method of using POINT and NOTES for DSNIIN/DSNIOUT, these datasets can not be allocated with DSNTYPE=LARGE.
Anyway, as documented in the CCUWPROC(MERGE) member comments, DSNIIN/DSNIOUT can be allocated as PSE MULTI-STRIPE files to allow for Multi-Volume Data Sets:
//* ***********************************************************
//* * THE DSNIIN/DSNINDEX WORK FILE CAN NOT BE MULTI-VOLUME *
//* * UNLESS IT IS A PSE MULTI-STRIPE FILE *
//* * THE PARAMETERS BELOW ALLOW DFSMS TO CALCULATE THE *
//* * NEEDED SPACE BY NUMBER OF DSNINDEX RECORDS WHERE *
//* * DA IS THE AVGREC VALUE - U(1), K(1024), M(1048576) *
//* * AND DAP/DAS ARE THE NUMBER OF RECORDS FOR PRIM/SEC *
//* * THE DEFAULT SPACE IS FOR 212992 DSNINDEX RECORDS *
//* * 1024 * 13 * 16 = 212992 *
//* ***********************************************************
So, changing the value of parms:
DA='K', U OR K OR M # OF RECS
DAP='13', PRIM # OF DSNINDEX RECS
DAS='13', SEC # OF DSNINDEX RECS
SWT='CYL', TYPE OF SORTWK ALLOC
SWP='3', PRIM SIZE OF SORTWK ALLOC
It is possible to adjust the space allocation of primary and secondary space of these files following the suggestions in the below KD:
MERGE message 4185 : adjust primary and secondary allocation for DSNIIN and DSNIOUT workfiles
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