How to Use This Manual

The Oracle Enterprise Manager Oracle Database and Database-Related Metric Reference Manual (hereafter referred to as the Oracle Database and Database-Related Metric Reference Manual) lists all the Oracle Database and database-related target metrics that Enterprise Manager monitors. This manual compiles in one place all the database and database-related target metric help available online, eliminating the need to have the Database Control Console up and running.

This preface describes:

• Structure of the Oracle Database and Database-Related Metric Reference Manual

• Background Information on Metrics, Thresholds, and Alerts

Structure of the Oracle Database and Database-Related Metric Reference Manual

This manual contains a chapter for the Oracle Database target and database-related targets for which there are metrics.

The metrics in each chapter are in alphabetical order according to category.

Metric Information

The information for each metric comprises a description, summary of the metric's "vital statistics", data source (if available), and user action. The following list provides greater detail:

• Description

  Explanation following the metric name. This text defines the metric and, when available, provides additional information pertinent to the metric.

• Metric Summary

  Explains in table format the target version, collection frequency, upload frequency, operator, default warning threshold, default critical threshold, consecutive number of occurrences preceding notification, and alert text for the metric. Examples follow.

• Data Source

  How the metric is calculated. In some metrics, data source information is not available.

• User Action

  Suggestions of how to solve the problem causing the alert.

Examples of Metric Summary Tables

This section provides examples of Metric Summary tables you will see in the Oracle Database and Database-Related Metric Reference Manual.

When default thresholds are not defined for a metric, only the target version and collection frequency are available.

The following table shows a metric where the server evaluation frequency is the same as the collection frequency.

The following table shows a metric where the server evaluation frequency is different from the collection frequency.

Definitions of Columns in Metric Summary Tables

As previously mentioned, the Metric Summary table is part of the overall metric information. The following table provides descriptions of columns in the Metric Summary table.

Abbreviations and Acronyms

To reduce the page count in this document, the following abbreviations and acronyms are used:

Background Information on Metrics, Thresholds, and Alerts

A metric is a unit of measurement used to determine the health of a target. It is through the use of metrics and associated thresholds that Enterprise Manager sends out alerts notifying you of problems with the target.

Thresholds are boundary values against which monitored metric values are compared. For example, for each disk device associated with the Disk Utilization (%) metric, you can define a different warning and critical threshold. Some of the thresholds are predefined by Oracle, others are not.

Once a threshold is reached, an alert is generated. An alert is an indicator signifying that a particular condition has been encountered and is triggered when one of the following conditions is true:

• A threshold is reached.

• An alert has been cleared.

• The availability of a monitored service changes. For example, the availability of an application server changes from up to down.

• A specific condition occurs. For example, an alert is triggered whenever an error message is written to a database alert log file.

Alerts are detected through a polling-based mechanism by checking for the monitored condition from a separate process at regular, predefined intervals.

Editing

Out of the box, Enterprise Manager comes with thresholds for critical metrics. Warning and critical thresholds are used to generate an alert, letting you know of impending problems so that you can address them in a timely manner.

To better suit the monitoring needs of your organization, you can edit the thresholds provided by Enterprise Manager and define new thresholds. When defining thresholds, the key is to choose acceptable values to avoid unnecessary alerts, while still being notified of issues in a timely manner.

You can establish thresholds that will provide pertinent information in a timely manner by defining metric baselines that reflect how your system runs for a normal period of time.

The metrics listed on the Edit Thresholds page are either default metrics provided by Oracle or metrics whose thresholds you can change.

Specifying Multiple Thresholds

The Specifying Multiple Thresholds functionality allows you to define various subsets of data that can have different thresholds. By specifying multiple thresholds, you can refine the data used to trigger alerts, which are one of the key benefits of using Enterprise Manager.The key in specifying multiple thresholds is to determine how the comparison relates to the metric threshold as a whole. What benefit will be realized by defining a more stringent or lax threshold for that particular device, mount point, and so on?For example, using the Average Disk I/O Service Time metric, you can define warning and critical thresholds to be applied to all disks (sd0 and sd1), or you can define different warning and critical thresholds for a specific disk (sd0). This allows you to adjust the thresholds for sd0 to be more stringent or lax for that particular disk.

Accessing Metrics Using the Grid Control Console

To access metrics in the Grid Control Console, use the All Metrics page associated with a particular target by doing the following:

1. From the Grid Control Console, choose the target.

2. On the target's home page, click All Metrics in the Related Links section.

3. On the All Metrics page, choose the metric of interest and click Help. The help for that metric displays.