This page displays a table that lists and provides information about each selected view. If you selected the “Add to existing view selection” option, the table lists previously selected rows and then newly selected rows.
In the Select column, as you select the views to be materialized, keep the following in mind:
The first view, which is the level 0 view, is selected by default. You cannot clear the selection.
The view selection is contiguous. Thus, for example, if you select the 10th view, all views from 1 to 10 are selected.
If previously materialized views are listed, they are selected. You cannot clear the selections.
Note: | For information about fine-tuning view selection, see the Oracle Essbase Database Administrator's Guide. |
The following columns provide information about the views:
Level Info—Level numbers, one number (thus, one member) per dimension. For dimensions that contain hierarchies, notations also identify hierarchy placement (level number/hierarchy number). Dimension hierarchies are numbered top down, starting with hierarchy 0.
Database Size (MB)—Estimated size of the database if the view (and all views that it depends on) is materialized. Each size value is graphed on the X-axis in the Database Size/Query Cost Graph.
Query Cost—Estimate of the average retrieval time required to retrieve values from the view. For the first view (selected by default), the estimation is the average of all possible queries. For views for which query tracking is used, the estimation is the average of the tracked queries. Therefore, a view may, under different conditions, display different estimates. To compute a percentage that evaluates the benefit of using a particular view, divide the query cost value for the view into the query cost value for using views that contain only level 0 values.
The following boxes display additional information:
Number of selected/all views—Ratio between the number of views selected for materialization and the total number of views
Total size of selected/all views—Ratio between the size of the database if the selected views are materialized and the size of the database if all views are materialized
When the view-selection process concludes, the Database Size/Query Cost graph is displayed. The graph plots the database size on the X-axis, and the cost of the query on the Y-axis. Individual-view and all-view values are identified by color.
As you review the graph, consider the following:
The point at which the line begins to curve from vertical to horizontal may represent the point at which the selection of additional views stops reducing query cost and begins increasing database size.
For optimum results, you may want to clear (not select) the views that follow the view associated with the veritcal-to-horizontal point.
If you want to base view selection on query tracking data, you select the “Use query tracking data during view selection” option. Because queries are tracked continuously, if the option is selected, each run of the wizard may product a unique set of views. If the option is not selected, Essbase Server assumes that each view is equally likely to be queried.
For detailed information about query tracking, see the Oracle Essbase Database Administrator's Guide. For instructions on how to enable or disable query tracking for a database, see Tracking Query Data for Aggregate View Selection.
Note: | The query data option is valid only for databases that contain aggregations. |
To begin the view-selection process, click Start. To stop the process, click Stop. If you click Stop and then Start, the selection begins anew; that is, views selected during the first process are not saved.