Saving the database

Before restructuring operations begin, i.e. before BCHANGE is started, you must switch off after-image logging (BALTER writes no after-images) and save the entire database or part of the database as required:

You must always save the following:

dbname.HASHLIB
dbname.COSSD
dbname.DBDIR
dbname.DBCOM

With regard to the user realms, you have two options:

• You save all the user realms before beginning the restructuring process, i.e.
  dbname.realmname-1
  .
  .
  dbname.realmname-n

• You use an analysis run with the statements
  REPORT IS YES
  EXECUTION IS NO
  to determine which user realms are needed
  and then you save only these realms in addition before the BALTER execution phase.

  Determining the user realms needed:

  After saving dbname.HASHLIB, dbname.COSSD, dbname.DBDIR and
  dbname.DBCOM, execute the restructuring process including the analysis run of BALTER with REPORT IS YES and EXECUTION IS NO. You can determine which user realms are needed from the analysis log for BALTER under REPORT OF ADDED, DELETED AND NEEDED AREAS.

  Realms may also be needed because anchor records of singular sets have to be recreated. Here BALTER attempts to prevent unnecessary relocations between the realms in order to limit the backup effort required in the user realms.

  Saving the needed user realms:

  Before restructuring using BALTER is performed and the EXECUTION IS YES statement is executed, save the user realms determined in the analysis phase:
  dbname.realmname-i
  .
  .
  dbname.realmname-j

For further information on saving a database, refer to the section "Saving and recovering a database in the event of errors" in the "Database Operation" manual.