Considerations for using the unload utilities

Certain considerations apply when using the unload utilities of IMS High Performance Unload.

Considerations for a logical parent's concatenated key
By default, for a logical child segment with a logical parent's concatenated key (LPCK) that is specified as VIRTUAL on the SEGM statement of the DBD, FABHURG1 returns blanks in the I/O area that usually contains LPCK, and FABHFSU returns binary zeros in the area.
Considerations for an unloaded data set used for reorganization
Unloaded data sets that are created under certain conditions cannot be reloaded with the IMS HD Reorganization Reload utility (DFSURGL0).
Considerations for database sharing
In general, like any other unload utility during reorganization, FABHURG1 and FABHFSU must have exclusive control of the database while they run. In some cases, however, you might want to read the database while it is being updated by IMS.
Considerations for HALDB Online Reorganization capable partitions
IMS High Performance Unload supports HALDBs. IMS High Performance Unload supports also the PHDAM or the PHIDAM partitions that are defined as HALDB Online Reorganization (OLR) capable.
Considerations for using a secondary index
A secondary index can be used to retrieve HIDAM or HDAM root segments. The target segment of the secondary index must be a root segment.
Considerations for unloading an IMS catalog
You can use IMS High Performance Unload to unload data from an IMS catalog.
Considerations for IMS-managed ACBs environment
When the IMS management of ACBs is enabled, IMS reads database descriptors (DBDs) from the IMS catalog instead of from the DBD library that is specified in the IMS DD statement.

Parent topic: Introduction to the unload utilities