Explain tab

The Explain tab displays a visual representation of the Db2 Explain plan. 

Related topics

Performance perspective

You can view the Db2 statement in the following formats:

  • Explain diagram - displays each step as a node and indicates the step's cost, type, and message severity level

    The node displays one of the following icons to indicate the highest severity of the message rules associated with that step (if a message rule exists):

    • Severe NW_cross_circle_red.png
    • Warning NG_exclamation_triangle_yellow.png
    • Informational NG_info_circle_blue.png

    To focus on specific steps, you can zoom in and out.

  • Explain tree - you can expand or hide steps to focus on specific steps

Graphical Explain enables you to perform the following tasks:

Task

Description

View step details

  1. Perform one of the following actions:
    • In the Explain diagram, click the step node.
    • In the Explain tree, click the node.
  2. In the Explain detail pane, select the Step Details tab to view the step information from the plan table.

View message rules

  1. Perform one of the following actions:
    • In the Explain diagram, click the step node.
    • In the Explain tree, click the node.
  2. In the Explain detail pane, select the Message Rules tab to view the message rules (both those delivered by BMC and user-defined message rules).

Toggle between the Explain diagram and Explain tree formats

To display the Explain diagram, click Show graph view NG_show_graph_view.png.

To display the Explain tree, click Show tree view NG_show_tree_view.png.

Zoom in and out

Move the Zoom slider or use the mouse wheel.

To change which section of the Explain diagram is displayed, click and hold the mouse button while moving the mouse.

To display the entire diagram on the page, click Fit on screen.

Enter full screen mode

Click Full screen NG_full_screen.png.

Exit full screen mode

Click Close NG_exit_full_screen.png.

Expand or hide steps in the Explain tree

Click the expansion arrow next to the step node.

 

 

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