Restrictions for IMS High Performance Unload

• For details of call types supported in each API set, see DL/I calls supported by each API set.
  • If APISET 1 or 2 is specified, or if the target is a non-HD database, the following restrictions are applied:
    • An unqualified or qualified SSA is not fully supported.
    • Three or more SSAs are supported restrictedly.
    • Command codes except for NULL('*-') command code are not supported.
    • Multiple qualification statements are not supported.
  • If APISET 3 is specified for non-HD database and the unsupported call is issued, HSSR Engine ends abnormally without passing the call to IMS DL/I.
  • A get-next call issued after GU calls that returned a GE status might not return the same segment as DL/I.
• For details about the EXEC DLI command types supported in each API set, see EXEC DLI commands supported by each API set. For the EXEC DLI commands, the restrictions corresponding those for the DL/I calls apply.

• HSSR calls using AIB interface are not supported.

  An HSSR call that uses the interface is passed to IMS's DL/I call handler and is processed as a DL/I call or an EXEC DLI command for the corresponding DL/I PCB.

• An HSSR application program that uses AIB system service calls might have problems. The use of AIB system service calls is not recommended.

• A data capture exit routine cannot issue an HSSR call.
• If an application program issues an HSSR call for the PCB that follows, the call is transferred to the DL/I language interface and the message FABH0671W is issued with RC=USREXIT. The reason that caused the message is as follows:
  • PCB is generated with PROCOPT=R
  • The DBD referred to by the PCB is generated with the data capture exit routine.

  In this case, therefore, the HSSR application program cannot take advantage of the HSSR Engine.

See Considerations for Db2 DL/I Batch interface.

See Considerations for checkpoint and restart.

See Consideration for database sharing.

In the ULU region, the virtual logical child segment is ignored. In the DLI and the DBB regions, the processing depends on the SKIPVLC control statement. For details of the SKIPVLC control statement, see SKIPVLC control statement.

The restriction applies to the unloading of databases for reorganization because the data set input to IMS HD Reorganization Reload utility does not contain virtually paired segments.

• A logical parent segment that has one or more logical children.
• A logical child segment that is physically paired.

• Having no segment types defined as data-sensitive by a SENSEG statement (this condition does not happen when you use a ULU region in unloading.)
• Having a user exit routine set a return code indicating that some segments should be skipped.

• When FABHURG1 retrieves a logical child segment for which the logical parent's concatenated key (LPCK) has been specified as VIRTUAL on the SEGM statement of the DBD, blanks are returned to the part of the I/O area where the LPCK is to be placed.

Therefore, you must specify a BLDLPCK control statement when unloading such a database if you specified the database in the DBIL= statement when running the IMS Database Prereorganization utility. For performance reason, you should not specify a BLDLPCK statement if you specified the database in the DBR= statement when running the Prereorganization utility.

• Migration unload of the secondary index is not supported.
• Migration unload of the HISAM database is not supported.
• If PTR=H or PTR=HB is defined as the parent segment of virtual logical child, FABHURG1 does not support the migration unload of the database.
• Fallback unload of the partitioned secondary index (PSINDEX) is not supported.