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.

In the ULU region, you can specify the name of the secondary index by using the following control statement:

For FABHFSU, DBD control statement.
For others, BYINDEX control statement.

In the DLI or the DBB region, the index name on these control statements is ignored. HSSR Engine uses the secondary index, which is coded by the PROCSEQ= parameter in the specified PCB.

When the secondary index is used, the value of the search field of the index segment is set to the key feedback area of the HSSR PCB, instead of the root key. User exits can specify a next root segment by the value of the search field.

Restriction

The following secondary indexes are not supported:

Secondary index whose target is not a root segment
Secondary index with symbolic pointing
Secondary index that contains index pointer segments with nonunique keys
Secondary index for databases other than HIDAM or HDAM