Overview of HALDB offline reorganization

An offline reorganization of a HALDB database can be done with one or more parallel processes. These processes unload one or more partitions and reload them.

If the database has secondary indexes or logical relationships, additional steps are not required. The HALDB self-healing process makes updates of pointers during the reorganization unnecessary. The amount of time required for a reorganization depends on the sizes of the partitions. Smaller partitions reduce the time. You can reduce your reorganization time by creating more partitions and reorganizing them in parallel.

The basic steps involved in reorganizing a HALDB database offline are:

Procedure

  1. Run the HD Reorganization Unload utility (DFSURGU0) to unload the entire database, a range of partitions, or a single partition.
  2. Optionally, initialize the partitions by running either of the following utilities:
    • HALDB Partition Data Set Initialization utility (DFSUPNT0)
    • Database Prereorganization utility (DFSURPR0)
  3. Run the HD Reorganization Reload utility to reload the database or partitions.
  4. Make image copies of all reloaded partition data sets.

The following figure shows the offline processes used to reorganize a HALDB database with logical relationships and secondary indexes. In this case, the partitions are reorganized by parallel processes. Each partition can be unloaded and reloaded in less time than unloading and reloading the entire database. This is much faster than the process for a non-HALDB full-function database. Additionally, no time is required for updating pointers in the logically related database or rebuilding secondary indexes. This further shortens the process.

Figure 1. Offline reorganization of a HALDB database
Figure depicts four partitions being reorganized independently by an unload and a reload. HALDB secondary indexes and logical relationships need no manual updates after a reorganization.