16.1 Overview
- Executor: User with the SELECT privilege for the target table
- The optimizing information collection utility collects information required in order to optimize the system based on cost and registers the information in a data dictionary table. Registered optimization information can also be deleted from the data dictionary table. The optimizing information collection utility provides the following functions:
- Function for collecting optimization information by retrieval
- Function for registering optimization information from an optimization information parameter file
- Conditions for executing the optimizing information collection utility
- You should execute the optimizing information collection utility when all the following conditions are satisfied:
- The cost-based optimization mode is 2.1
- No application that involves updating operations is running.2
- There are many complex searches, such as join searches.
- There exists a test environment with the same data as in the real environment.3
- 1
- If the cost-based optimization mode is not 2, you can still execute the utility if the optimizing information collection level is lvl2.
- 2
- If an application that involves updating operations is running, but the optimizing information collection level is lvl1 and the number of rows in the table has not changed, you can use the utility.
- 3
- If there is no test environment with the same data as in the real environment, but you register the optimization information using a parameter file that contains optimized information, you can use the utility.
- Organization of this section
- 16.1.1 Collecting optimization information by retrieval
- 16.1.2 Registering optimization information from an optimization information parameter file
- 16.1.3 Maximum number of concurrently executable utilities