Index partitioning

You can build partitioned indexes by using specific command syntax with the BUILD command. PFXLIB contains information for the partitioned index so that Fast Path Indexer/EP can determine the index partitions that are defined to a particular index. The Fast Path Indexer/EP BUILD command determines the index partitions that are defined to a particular index from the control block in the PFXLIB (for a PFX index) or ACBLIB (for an IBM native index). The following figure illustrates a partitioned PFX SHISAM or HISAM index.

PFXLIB view of partitioned SHISAM indexes and HISAM indexes.png


You can include 500 partitions in a PFX partitioned index and 101 partitions in an IBM native index. A non-partitioned SHISAM or HISAM index data set has a 4-GB limit. If you use partitioning, however, you can include as many as 500 partitions, each containing 4 GB of space. Each of these partitions must mirror the original SHISAM or HISAM index design. Partitions let you use the SHISAM or HISAM structure while including much more information than can fit into one SHISAM or HISAM index data set.

When you execute the BUILD command, it builds all partitions; Fast Path Indexer/EP no longer supports building specific partitions.

Note

You must write your own exit routine to tell Fast Path Indexer/EP how to distribute the index data into the partitions.

IBM provides a sample partition exit in member DBFPSE00 in the IMS.SDFSSRC library.

When you partition your Fast Path Indexer/EP SHISAM or HISAM indexes, you instruct the indexes to distribute data by using the vertical sequential access method (default) or the lateral sequential access method. You indicate the access method in the PFX definition control block. For more information, see Primary-DEDB-and-PFX-index-control-block-maintenance. For information about IBM native index requirements, see the IBM documentation.

The following examples show how to select vertical or lateral processing for PFX SHISAM or HISAM indexes:


Related topic

Index-build-utility


 

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