Restoring the database after updates are made

If you have updated the database after converting it to HALDB, your options for restoring the database to its non-HALDB state are limited.

If the data no longer fits in the VSAM 4 GB size limit or the OSAM 8 GB size limit of a non-HALDB database, you cannot restore it without taking extraordinary steps. The natural growth of the database or even the conversion of virtual pairs to physical pairs can cause the database to grow beyond these non-HALDB size limits. In the unlikely event that you need to restore the non-HALDB database structure and your data no longer fits into the non-HALDB database size limitations, contact IBM® Software Support.

If the amount of data is still within the space limitations of a non-HALDB database, you can restore the database by completing the following steps:

Procedure

  1. Unload the database by using the HD Reorganization Unload utility (DFSURGU0) and the FALLBACK=YES control statement. The HD Reorganization Reload utility locates the paired logical children and saves the information that is needed for fallback in the prefix of the output data. The prefix that is created by the HD Reorganization Unload utility contains the information that is required to create the new segment prefix when the data is reloaded.
  2. Restore the DBD of the non-HALDB database.
  3. Delete the HALDB database information from the RECON data set.
  4. Register the non-HALDB database with DBRC.
  5. Run the Database Prereorganization utility (DFSURPR0) and specify the DBR control statement.
  6. Reload the non-HALDB database by using the HD Reorganization Reload utility (DFSURGL0).
  7. If the database has secondary indexes, restore the secondary indexes by rebuilding them after the fallback process is complete for the indexed database.
  8. If the database is logically related to another database, you must perform fallback for all of the logically related databases at the same time.
  9. Take an image copy of the database data sets.