Spotlight on Oracle 11.0 - Getting Started Guide

Identify And Mark Trend Changes

You can see Trend Changes in Predictive Diagnostics time-based charts when the pattern of usage of a database changes. A trend change can occur in a SQL Performance, Bottlenecks, or Performance Modeling chart.

Mark trend changes by using these controls on the chart toolbar:

Toolbar	Description
Add Trend Change	Mark trend changes on the Predictive Diagnostics chart. In the Add Trend Change window: Use the arrow buttons to position the trend change line on the chart. (The trend change line appears on the chart as you use the controls.) Add some text in the Description box to identify the trend change. Select Also Create... to add the same trend change to related Predictive Diagnostics charts.
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
Display Excluded Data	Show data that was ignored because it fell outside one of the Peak Processing Periods.
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.

• You can expect (and should mark) a trend change when you change the environment where the SQL statements are executed — for example, when you install a new version of Oracle, or when you upgrade the platform that hosts the database.
• Other trend changes may be clear from a visual inspection of the raw data displayed in the chart. If you believe you can see such a change, you should mark it. (If you add a trend change line where NO real trend change exists, you will NOT change the nature of Spotlight's prediction, but you WILL make it less accurate, as Spotlight is using fewer data points to generate the prediction.)

Note: Trend changes in Impending Bottlenecks and Performance Modeling (and their sub-pages) apply globally to ALL the time-based charts for timed statistics and database resources. A bottleneck or resource ceiling is likely to be a feature of the system itself and NOT depend specifically on the transactions in progress or the timed statistics used to analyze the system.