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Spotlight on Oracle 10.7 - Getting Started Guide

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What Database Load Can Be Supported?

Note: Available for Oracle 10.2 and later.

Use this page to predict what database load can be supported by a hypothetical mix of CPU, memory, and disk resources.

To open this page

  1. Select the Spotlight on Oracle connection in the Spotlight Browser.
  2. Click Predictive Diagnostics | What Database Load Can Be Supported?.

Set the criteria

Choose these parameters for your analysis.

Note: The parameter settings initially are the same as those in the What Database Resources Are Needed? page.



Perform an analysis of...

Select Real Data (your database) or Sample Data (to experiment with).

Note: Spotlight takes some time (typically about 10 days) to collect enough data to make valid predictions on the future performance of your Oracle instance. In the meantime use the prepared sample data to learn more about Predictive Diagnostics and how it works.


Choose a date to use as the start date for the period to be analyzed. Choose a date for which recorded data exists; for example, you cannot choose a date later than today's date.

Processing period...

Select an activity period to use for your prediction. The more selective this is the better the prediction.

Tip: To define new processing periods or redefine an existing processing period see Peak Processing Periods.

Predict forward until...

Select an end date for the prediction.

Using...for database throughput

Choose a metric to represent the total amount of work performed. Throughput Metrics

Option Description

Logical reads/s

The rate of requests for database blocks (buffer gets).

Rows processed/s

The rate at which rows are processed by SQL statements.

SQL executions/s

The rate at which SQL statements are executed.


The rate of transactions on the database. A transaction contains one or more SQL statements. It begins with the execution of the first SQL statement, and ends when the transaction is either committed or rolled back.

Using...for database concurrency

Choose a metric to represent database concurrency.Concurrency Metrics

Option Description

Connected sessions

The average number of user sessions connected to the database at the time.

Active sessions

The average number of user sessions that are performing some database activity at the time.

Note: High values for Active sessions can be generated by a single session performing SQL queries in parallel OR by many sessions performing many SQL queries of short duration.

Because of this, Active sessions also may be considered a measure of the total amount of work performed (throughput).

Customized SQL

Use a customized concurrency metric defined in the Database Throughput And Concurrency page for database throughput and concurrency.

Predict the load

Predict the database load that can be supported by the entered combination of CPU, memory, and disk resources.

Note: Because the values are entered as a percentage of the resources now available, the prediction makes no judgments on how database resources may be implemented. (For example, a prediction for 200% of the current CPU resources does not depend on whether the increase is implemented as a more powerful single CPU, multiple additional CPUs, or a combination of both.)



Current CPU

Enter a hypothetical value for the CPU resources available to the database.

Current Memory

Enter a hypothetical value for the memory resources available to the database.

Current Disk

Enter a hypothetical value for the disk resources (Disk Latency And Disk Throughput) that can be made available to the database. Choose the metric that is more appropriate to the database environment.

Analysis of resource utilization by time, throughput, and concurrency

The charts display the prediction for database load resulting from the given combination of CPU, memory, and disk resources.



Resource Utilization by Time

How database resources will be consumed over time, given the hypothetical values for CPU, memory, and disk resources.

Resource Utilization by Database Throughput

How resource utilization varies with the metric (logical reads/s, rows processed/s, SQL executions/s, or transactions/s) chosen to represent database throughput.

Resource Utilization by Database Concurrency

How resource utilization varies with the metric (connected sessions, active sessions, or a customized metric) chosen to represent database concurrency.


  • The graphs plotted on each chart indicate the most likely values for the prediction. Prediction Interval are omitted for the sake of clarity.
  • The broken red line in each chart indicates the current ceiling for each resource.

Analysis Summary and Recommendations

The pane at the right provides a summary of the analysis used to draw the charts on the left, and indicates:

  • The database resources whose availability may lead to performance problems.
  • When resource ceilings will be reached.
  • How to reduce the impact of a resource limit by augmenting resources.


  • Click a Show Details item to see more details on the summary.
  • Click a link to go to a related Predictive Diagnostics page, or to view additional information.


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