Optimizer_mode For 11R2 (Doc ID 1537762.1)

In this Document

Goal

Solution

APPLIES TO:

Oracle Communications Billing and Revenue Management - Version 7.5.0.0.0 and later
Information in this document applies to any platform.
*** Checked for relevance on 09-05-2014 ***

GOAL

The user is upgrading to 11gR2 DB. What is the recommended value for the parameter "optimizer_mode"?
 

As per Oracle DB documentation, three values are possible:

• first_rows_n

  The optimizer uses a cost-based approach and optimizes with a goal of best response time to return the first n rows (where n = 1, 10, 100, 1000).

• first_rows

  The optimizer uses a mix of costs and heuristics to find a best plan for fast delivery of the first few rows.

• all_rows (default value)


  The optimizer uses a cost-based approach for all SQL statements in the session and optimizes with a goal of best throughput (minimum resource use to complete the entire statement).

 

SOLUTION

The recommended value for "optimizer_mode" is the default value of "all_rows".