Statistics of the View

The Cost-based optimization uses the statistics of the views to estimate the cost of alternative execution plans for queries.

To gather the statistics of a view, select Enable statistics and then, click Gather statistics for selected fields. The Tool will instruct the Server to gather and store the statistics of the view: number of rows, number of different values of each field, etc. After the process has finished, the table below will be filled in. You can also set the statistics manually by entering the Number of rows and/or filling in the values in the table below.

The statistics of a view can be disabled by clearing the Enable statistics box. When the statistics of a view are disabled, they are not deleted but they will not be used in the cost-based optimization process.

The section Cost-Based Optimization explains how the cost-based optimization works.

The statistics of a view are not included in version control because they are environment-dependent.