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SQL Optimizer for SAP ASE 3.9.1 - Release Notes

Selected Index Set

The Select Index Set tab of the Batch Run Criteria window is used to select or deselect which Index Sets are applied before retrieving the run time for the original SQL statement. All Index Sets are selected by default. By clicking a row, an Index Set can be selected or deselected. The selected Index Sets are prefixed with a Blue Checkmark image\I_BlueCheckmark.gif.

Note: The higher the Estimated I/O value does not necessarily mean lower performance. If possible, it is recommended that all alternatives be tested.

To select or unselect all the index sets

Right click and select Unselect All or Select All.

The Used Index can be de-selected only if the Used Index checkbox is not selected on the SQL Termination and Batch Termination tab and the Always run Used Index first option in the Selected Index tab is not selected.

To change the order the Index Sets are tested

  1. Click the row.

  2. Click Move Upimage\B_MoveUp.gif or Move Downimage\B_MoveDown.gif.

To change the order of the Index Sets by sorting

The Index Sets are ranked by Est. I/O Cost by default, with the exception for the Used Index which is placed at the top. You can sort either the Est. I/O column or the Index Set column by clicking the column heading.

To always run the Used Index first

Select the Always run Used Index first checkbox.

Note: This checkbox is dimmed if Used Index is selected as the SQL Termination or Batch Termination criteria.

To select or unselect a group of Index Sets according to the Est. I/O Cost values

  1. Select the Apply Filtering checkbox.

  2. Click SQL Selection Filterimage\B_SQLSelectionFilter.gif.

Note: The Est. I/O Cost is only available if you have already obtained the query plans.


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