To open the SQL Transaction Details page
The Cost Summary for the SQL statement contains this information:
This shows how the cost rate of the SQL statement will change between now and the end-date. The Cost per Second value is calculated on the Cost Metric (for example, buffer gets) used for the projection.
Chart data points
Data Points | Description |
---|---|
The raw data ( |
The actual data used to generate the chart. |
New data (in a contrasting color) | New data (when available) is data collected AFTER the raw data was analyzed. |
The shaded region | The Prediction Interval that is based on the raw data. |
A vertical trend change line |
If displayed, it shows the early data follows a different trend from the more recent data. Trend Changes The early data is not used in making predictions. Note: You can set a Trend Change line via the chart toolbar. |
Chart toolbar
Toolbar | Description |
---|---|
Add Trend Change |
Mark trend changes on the Predictive Diagnostics chart. In the Add Trend Change window:
|
Delete Trend Change |
Remove trend change lines from the chart. In the Delete Trend Change window, select the Delete? option that corresponds to the line you want to remove. |
Accept suggested trend change |
If Predictive Diagnostics notices a possible trend change it will mark it on the chart and prompt you to accept or reject it. |
Reject suggested trend change |
|
Reanalyze |
Generate a new Prediction Interval on the chart from the raw data. |
You can mark a trend change on the chart wherever you like, but the trend change is valid only in circumstances where it represents a REAL change in Oracle's handling of SQL statement executions, system bottlenecks, or database resources.
Note: Trend changes in SQL Performance Predictions charts apply only to the specified chart for the selected SQL statement. Predictions on the execution of SQL statements are specific to the SQL statements themselves. If one SQL statement will perform poorly on the Oracle database as data volumes and SQL execution rates increase, the same does not necessarily apply to other SQL statements. Equally, a SQL statement whose performance scales adequately with respect to one cost metric (CPU time, for example) may not scale adequately with respect to another (Disk Reads, for example).
Predictive Diagnostics forecasts how the execution of SQL statements will perform in the future as data volumes and execution rates increase.
You may also want to view further information on the execution plan that Oracle applies to a particular SQL statement. You can do this via the Spotlight Explain Plan.
The full text of the SQL statement used to generate the contents of the summary and chart on this page.
Action |
Description |
---|---|
Click Explain SQL |
Explain the SQL via the Explain Plan. Tools | Explain Plan |
Click SQL Optimizer |
Display context-sensitive tuning advice for SQL statements via SQL Optimizer (or SQL Tuning). Tools | SQL Optimizer Note: For more information on SQL Optimizer, see the SQL Optimizer documentation. |
Right-click the SQL Text window and select Format SQL. | Display the SQL statement in a more readable form. |
Note: If the SQL cannot be explained, the Explain Plan and SQL Optimizer (SQL Tuning) options may be unavailable.
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