Comparing access plans for two sets of identical packages that are in two different collections

You can find out whether rebinding packages after making changes to your system would change access plans and whether those changes would slow the execution of your SQL statements.

Before you begin

Ensure that the prerequisites for comparisons that use packages are met.

About this task

Use this option in scenarios such as:

Procedure

To compare access plans for two sets of identical packages that are in two different collections:

  1. Before making changes to your system, bind the packages that you plan to analyze, setting the EXPLAIN option to YES.
  2. Make changes to your system that you believe might affect the access plans for the statements that are in those packages.
  3. Bind the same packages to a new collection, setting the EXPLAIN option to YES.
  4. Create a comparable workload and run the comparison. A comparable workload is a workload that you create specifically for the comparison. It a logically grouping of both the packages that are in the original collection and the packages that are in the new collection.
    1. In the Data Source Explorer, connect to the DB2 for z/OS® subsystem on which the collections are located.
    2. Right-click the connection and select Analyze and Tune > Start Tuning.
    3. Click the Manage tab on the left side of the workflow assistant to open the Manage section.
    4. On the Manage Workloads page, click the Create Workload for Comparison icon, which is at the top of the page and looks like this: Create Workload for Comparison icon
    5. Follow the steps in the Create Workload for Comparing Access Plans in Packages wizard.
  5. On the Comparison History page, select the comparison and click Review Results.

Results

The View Comparison Results by Package Summary page opens. Double-click listed packages to see the comparisons of individual statements.

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