The database structure modification utility (pdmod command) is used to migrate a HiRDB single server configuration to a HiRDB parallel server configuration. The RDAREAs are migrated from the single server to the dictionary and back-end servers by executing the alter HiRDB mode to parallel statement provided by the database structure modification utility.

The following figure shows migration of RDAREAs using the database structure modification utility.

Figure 11-1 Migration of RDAREAs using the database structure modification utility

(a) Backing up data before migration

The pdfbkup command should be used to back up the HiRDB files and HiRDB file system areas that contain the following RDAREAs:

• User RDAREAs
• User LOB RDAREAs

(b) Handling of stored procedures and stored functions

When a system is migrated from a HiRDB single server configuration to a HiRDB parallel server configuration, stored procedures and stored functions (stored functions for user-defined functions) created for the HiRDB single server configuration are no longer valid. The stored procedures and stored functions must be re-created with ALTER ROUTINE after migration to the HiRDB parallel server configuration has been completed.

(c) Handling of user LOB RDAREAs

User LOB RDAREAs containing LOB data and the user RDAREAs containing the LOB column structure base table for the LOB data must be placed on the same back-end server. Otherwise, the back-end servers might terminate abnormally when the RDAREAs are accessed.

It can be verified that the RDAREAs have been placed on the same back-end server by referencing the SQL_RDAREA, SQL_TABLES, and SQL_DIV_COLUMN dictionary tables after migration has been completed.

(d) Handling of RDAREAs for lists

RDAREAs for lists and user LOB RDAREAs containing the base table for the lists must be placed on the same back-end server.