Reorganizing the database

Reorganizing a database means changing how the data in the database is organized to improve performance.

In some cases, reorganizing a database might also refer to modifying the database's structure or the structure of the records and segments in the database. Although this topic focuses on changing how data is organized, you can use many of the reorganization utilities discussed here to make structural changes as well.

Two database types, DEDB and HALDB, support online reorganization in addition to the offline methods of reorganization discussed here.

For full-function databases, CI reclaim can also improve performance of DL/I calls to VSAM key sequenced data sets. CI reclaim reduces the number of empty CIs that are read on DL/I calls.