Oracle7 Server Concepts

Licensing

Usually, Oracle is licensed for use by a maximum number of named users, or by a maximum number of concurrently connected users. The database administrator is responsible for making sure that the site complies with its license agreement. Oracle's licensing facility helps database administrators track and limit the number of sessions concurrently connected to an instance, or to limit the number of users created in a database, and thereby ensure that the site complies with the Oracle license agreement.

The database administrator controls the licensing facilities and can enable the facility and set the limits. He/she can also monitor the system's use. If the database administrator discovers that more than the licensed number of sessions need to connect, or more than the licensed number of users need to be created, he/she can upgrade the Oracle license to raise the appropriate limit. (To upgrade an Oracle license, you must contact your Oracle representative.)

Note: In some cases, Oracle is not licensed for either a set number of sessions or a set group of users. For example, when Oracle is embedded in an Oracle application (such as Oracle Office), run on some older operating systems, or purchased for use in some countries, it is licensed differently. In such cases only, the Oracle licensing mechanisms do not apply and should remain disabled.

The following sections explain the two major types of licensing available for Oracle.

Concurrent Usage Licensing

In concurrent usage licensing, the license specifies a number of concurrent users, which are sessions that can be connected concurrently to the database on the specified computer at any time. This number includes all batch processes and on-line users. Also, if a single user has multiple concurrent sessions, each session counts separately in the total number of sessions. If multiplexing software (such as a TP monitor) is used to reduce the number of sessions directly connected to the database, the number of concurrent users is the number of distinct inputs to the multiplexing front-end.

The concurrent usage licensing mechanism allows a database administrator to do the following:

An administrator can set a limit on the number of concurrent sessions that can connect to an instance by setting the LICENSE_MAX_SESSIONS parameter. Once this limit is reached, only users who have the RESTRICTED SESSION system privilege can connect to the instance; this allows database administrators to kill unneeded sessions, allowing other sessions to connect.

An administrator can set a warning limit on the number of concurrent sessions that can connect to an instance by setting the LICENSE_SESSIONS_WARNING parameter. Once the warning limit is reached, Oracle allows additional sessions to connect (up to the maximum limit described above), but sends a warning message to any user with RESTRICTED SESSION privilege who connects and records a warning message in the database's ALERT file.

The database administrator can set these limits in the database's parameter file so that they take effect when the instance starts. The administrator alternatively can change them while the instance is running by using the ALTER SYSTEM command. This is useful for databases that cannot be taken offline.

In addition, the session licensing mechanism allows a database administrator to check the current number of connected sessions and the maximum number of concurrent sessions since the instance started. The V$LICENSE view shows the current settings for the license limits, the current number of sessions, and the highest number of concurrent sessions since the instance started (the session "high water mark"). The administrator can use this information to evaluate the system's licensing needs and plan for system upgrades.

For instances running with the Parallel Server, each instance can have its own concurrent usage limit and warning limit. The sum of the instances' limits must not exceed the site's concurrent usage license. See the Oracle7 Server Administrator's Guide for more information.

The concurrent usage limits apply to all user sessions, including sessions created for incoming database links. They do not apply to sessions created by Oracle or recursive sessions. Sessions that connect through external multiplexing software are not counted separately by the Oracle licensing mechanism, although each contributes individually to the Oracle license total The database administrator is responsible for taking these sessions into account.

Named User Licensing

In named user licensing, the license specifies a number of named users, where a named user is an individual who is authorized to use Oracle on the specified computer. No limit is set on the number of sessions each user can have concurrently, or on the number of concurrent sessions for the database.

Named user licensing allows a database administrator to set a limit on the number of users that are defined in a database, including users connected via database links. Once this limit is reached, no one can create a new user. This mechanism assumes that each person accessing the database has a unique user name in the database and that no people share a user name.

The database administrator can set this limit in the database's parameter file so that it takes effect when the instance starts. The administrator can also change it while the instance is running by using the ALTER SYSTEM command. This is useful for databases that cannot be taken offline.

If multiple instances connect to the same database with the Parallel Server, all instances connected to the same database should have the same named user limit. See Oracle7 Parallel Server Concepts & Administration for more information.