Tools | Explain Plan
|Tools | Explain Plan allows you to determine the execution plan that Oracle applies to a particular SQL statement. Spotlight on Oracle allows you to view graphical representations of the execution plan for SQL statements being executed by a user, or for those identified by the Top SQL Page.
To open the Explain Plan Window
| Location | Instruction |
|---|---|
| From anywhere in Spotlight. |
Click Tools | Explain Plan. |
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From Drilldown Pages:
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Click |
.Note: To close the Explain Plan Window click Exit Explain 
SQL Text Window
Show the SQL Statement being tested in the Explain Plan window.
| Control | Description |
|---|---|
| The SQL Statement |
View, modify or re-enter the SQL statement and then regenerate the Explain Plan. |
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Show / Hide the SQL Text Window. |
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(Re)generate the Explain Plan for the SQL statement. |
Operation Table
The table is a tree structure of the operations required to perform the SQL query.
Notes:
- Select Expand to expand all steps in the table.
- Select Show Explanations to show an explanatory tool tip when the mouse hovers over an item in the table.
- Show column and index data for the database object in the step highlighted in the Operation table.
| Column | Description |
|---|---|
|
Operation |
The action on the dataset. |
|
Step |
The sequence of the actions. The following tables describe some of the common execution steps that you may encounter: |
|
Object |
The object name. |
|
Cost |
The cost of this operation. The values in RED in this column represent the most expensive steps—the critical path—in each level of the explain plan. (When multiple steps in the same level are on the critical path, only the first step will be shown in red.) |
|
Rows |
The number of processed rows for this operation. |
|
Bytes |
The number of bytes processed for this operation. |
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Other |
This shows the operation on the object as being either serial or parallel. |
| Control | Description |
|---|---|
 |
Show column and index data for the database object in the step highlighted in the Operation table. More details about the Describe table are found in the associated text boxes:
|
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Show the Explain Plan as a diagram. The critical path through the SQL query is represented by RED lines and RED-bordered icons. |
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Show the Explain Plan as text. The critical path through the SQL query is represented by RED text. |