Introduction to Physical Sequence Sort for Reload
The Physical Sequence Sort for Reload utility (PSSR) sorts an unloaded database data set created from an HDAM, a PHDAM, a HIDAM, a PHIDAM, a HISAM, or a SHISAM database. The utility helps preventing cascading for an HDAM or a PHDAM database and produces reports about database sizes and randomizer performance.
Considerations before using PSSR
The following considerations apply due to the changes made to IMS™ High Performance Load Version 2 Release 1.
If you reload an HDAM or a PHDAM database by using IMS High Performance Load Version 2 Release 1 or later, the input data must be in the order of hexadecimal value bbbbbbrr that represents the result of randomizing module conversion. bbbbbb is the block number and rr is the RAP number.
This change was made because direct I/O during the reload process was eliminated to improve performance in IMS High Performance Load Version 2 Release 1. In order to eliminate direct I/O, data must be sorted in sequence before loading occurs. You can specify the SORT control statement in the FRRIN data set to sort the unloaded data in the reload step. Instead of using the SORT control statement, you can run PSSR before reloading. For details about the SORT control statement, see SORT control statement.
The SORTOUT2 data set cannot be used to prevent cascading. The data set cannot be used, by IMS High Performance Load Version 2 Release 1 or later, as an input for reload. To prevent cascading and avoid degradation of performance in reloading, it is recommended that you use the SORT=YES and the SEARCH=-nnn parameter instead of using PSSR. If you reload an HDAM or a PHDAM by using the IMS HD Reorganization Reload utility, you can use the SORTOUT2 data set to prevent cascading.
The following topics provide information about Physical Sequence Sort for Reload.