CA-IDMS: All supported releases.
There are records in the database being unloaded that are defined with the CALC location mode and allow DUPLICATES.
By default, REORG and the IDMS unload/reload process attempt to maintain the order of duplicates within a particular key value for CALC record types.
To do this, processing requirements increase in proportion to the square of the number of duplicates of a given value. In some cases, the difference can be extreme.
Optional bit 93 should be considered.
It will greatly reduce the runtime of the unload at the expense of not maintaining the original order of duplicates.
What this means is that any code which processes duplicate CALC key values (using OBTAIN CALC and then OBTAIN DUPLICATE in a loop) may not read them in the same order after the REORG or unload/reload as it would have before.