Upgrade Guide for DB2 UDB for z/OS and OS/390 > Database and UI Upgrade Planning > Planning Your Upgrade >

New Database Schema Structure in Release 7.7

Siebel offered a new database schema structure in Release 7.7 that has the following characteristics:

• One table in each tablespace
• One tablespace in each database

This new approach is referred to as the 1:1:1 model. Customers may want to switch to this database schema structure from their current database schema structure because it is more efficient.

In previous releases, the database schema was built using approximately 20 databases, each of which contained multiple tablespaces. Each of these tablespaces (if non-partitioned) contained multiple tables. Release 7.7 contains thousands of databases. For example, an SIA installation has approximately 2700 databases. Each database has one tablespace and each tablespace has one table.

This model meets IBM recommendations and prevents database descriptor (DBD) locking and logging. These issues arise due to the increasing intensity of DB2 DML and DDL operations and the interaction of these operations with the DBD. The DBD is locked when information about the DB2 objects contained by the DBD is requested and accessed. In general, the more objects a DBD contains, the more probable that a DBD lock will be requested when information about a child object of the DBD is accessed.

Locks are acquired on the DBD table space (DBD01) if a DBD is not in memory (EDM pool). If the DBD is in the EDM pool, no lock is acquired on it if the SQL being run is static. However, most SQL executed by Siebel applications is dynamic; this means locks are acquired on the DBD. For more information on DBD locking, refer to the IBM document, DB2 UDB for OS/390 and z/OS V7 Administration Guide.

The adoption of the 1:1:1 model for Release 7.7 means that all upgrade teams must decide how much of this new model to deploy. Upgrade teams have the following options:

• Create all tables in the 1:1:1 model.

  New 7.7 tables will be created in the 1:1:1 model and the Siebel supplied storage control file is used for the upgrade.

• Create new tables in the 1:1:1 model and maintain existing tables in their current tablespace if possible.

  The following scenarios arise if you select this latter option:

  • Some existing tables need to be moved to incorporate the addition of new columns.
  • Some existing tables need to be moved, because they have been extended and the addition of new columns causes the table's LRECL to exceed that of the tablespace. This necessitates the use of the extract and merge methodology to create the storage control file. For more information on this methodology, see Extracting the Storage Control File.
  • Tables that are to retain the existing format are merged into the template control file which employs the 1:1:1 model.

For both options, enter existing tables that are to be migrated to the 1:1:1 model in the file override.inp.

For more information on using storage control file, see Implementing Siebel eBusiness Applications on DB2 UDB for z/OS and OS/390.