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Setting Oracle Database Optimizer Mode for a Siebel Upgrade

Upgrades: All Siebel upgrades.

Environments: Development, production test, production.

Databases: Oracle only.

This topic is part of an upgrade process. See How to Perform a Siebel Database Upgrade.

Oracle 9i

You can run the development upgrade, production test upgrade, and the production upgrade in either Rule Based Optimizer (RBO) mode or in Cost Based Optimizer (CBO) mode.

You need not run all environment upgrades in the same mode. For example, you can run the development environment upgrade in RBO mode and the production test environment upgrade in CBO mode.

Oracle 10g

Run all environment upgrades in CBO mode.

Setting the Optimizer Mode

Set the optimizer mode (OPTIMIZER_MODE) in init.ora as follows:

• For RBO, set the value to RULE.
• For CBO, set the value to CHOOSE.

Do not use the other OPTIMIZER_MODE settings.

Related Topics

Siebel Technical Note 582 on supported optimizer modes for Oracle databases.

Siebel Alert 1011 on supported optimizer modes for upgrading Oracle databases.