Oracle helps you ensure that your site complies with its Oracle Server license agreement. If your site is licensed by concurrent usage, you can track and limit the number of sessions concurrently connected to a database. If your site is licensed by named users, you can limit the number of named users created in a database. In either case, you control the licensing facilities, and must enable the facilities and set the appropriate limits.
To use the licensing facility, you need to know which type of licensing agreement your site has, and what the maximum number of sessions or named users is. Your site may use either type of licensing (concurrent usage or named user), but not both.
Note: In a few cases, a site might have an unlimited license, rather than concurrent usage or named user licensing. In these cases only, leave the licensing mechanism disabled, and omit LICENSE_MAX_SESSIONS, LICENSE_SESSIONS_WARNING, and LICENSE_MAX_USERS from the parameter file, or set the value of all three to 0.
See Also: For information about the initial installation procedure, see "Edit New Parameter Files" ![[*]](jump.gif)
.
In addition to setting a maximum concurrent session limit, you can set a warning limit on the number of concurrent sessions. After this limit is reached, additional users can continue to connect (up to the maximum limit); however, Oracle writes an appropriate message to the ALERT file with each connection, and sends each connecting user who has the RESTRICTED SESSION privilege a warning indicating that the maximum is about to be reached.
If a user is connecting with administrator privileges, the limits still apply; however, Oracle enforces the limit after the first statement the user executes.
In addition to enforcing the concurrent usage limits, Oracle tracks the highest number of concurrent sessions for each instance. You can use this "high water mark."
See Also: For information about terminating sessions, see "Terminating Sessions" .
For information about Oracle licensing limit upgrades, see "Viewing Licensing Limits and Current Values" .
Warning: Sessions that connect to Oracle through multiplexing software or hardware (such as a TP monitor) each contribute individually to the concurrent usage limit. However, the Oracle licensing mechanism cannot distinguish the number of sessions connected this way. If your site uses multiplexing software or hardware, you must consider that and set the maximum concurrent usage limit lower to account for the multiplexed sessions.
See Also: For more information about setting and changing limits in a parallel server environment, see the Oracle7 Parallel Server Concepts & Administration guide.
LICENSE_MAX_SESSIONS = 80
If you set this limit, you are not required to set a warning limit (LICENSE_SESSIONS_WARNING). However, using the warning limit makes the maximum limit easier to manage, because it gives you advance notice that your site is nearing maximum use.
Set the session warning to a value lower than the concurrent usage maximum limit (LICENSE_MAX_SESSIONS).
ALTER SYSTEM SET LICENSE_MAX_SESSIONS = 100;
The following statement changes both the warning limit and the maximum limit:
ALTER SYSTEM
SET LICENSE_MAX_SESSIONS = 64
LICENSE_SESSIONS_WARNING = 54;
If you change either limit to a value lower than the current number of sessions, the current sessions remain; however, the new limit is enforced for all future connections until the instance is shut down. To change the limit permanently, change the value of the appropriate parameter in the parameter file.
To change the concurrent usage limits while the database is running, you must have the ALTER SYSTEM privilege. Also, to connect to an instance after the instance's maximum limit has been reached, you must have the RESTRICTED SESSION privilege.
Warning: Do not raise the concurrent usage limits unless you have appropriately upgraded your Oracle Server license. Contact your Oracle representative for more information.
This mechanism operates on the assumption that each person accessing the database has a unique username, and that there are no shared usernames. Do not allow multiple users to connect using the same username.
See Also: For instances running with the Parallel Server, all instances connected to the same database should have the same named user limit. See the Oracle7 Parallel Server Concepts & Administration guide for more information.
LICENSE_MAX_USERS = 200
If the database contains more than LICENSE_MAX_USERS when you start it, Oracle returns a warning and writes an appropriate message in the ALERT file. You cannot create additional users until the number of users drops below the limit, you should delete users, or upgrade your Oracle license.
ALTER SYSTEM SET LICENSE_MAX_USERS = 300;
If you try to change the limit to a value lower than the current number of users, Oracle returns an error and continues to use the old limit. If you successfully change the limit, the new limit remains in effect until you shut down the instance; to change the limit permanently, change the value of LICENSE_MAX_USERS in the parameter file.
To change the maximum named users limit, you must have the ALTER SYSTEM privilege.
Warning: Do not raise the named user limit unless you have appropriately upgraded your Oracle license. Contact your Oracle representative for more information.
SELECT sessions_max s_max,
sessions_warning s_warning,
sessions_current s_current,
sessions_highwater s_high,
users_max
FROM v$license;
S_MAX S_WARNING S_CURRENT S_HIGH USERS_MAX
-------------------------------------------------------
100 80 65 88 250
To see the current number of named users defined in the database, use the following query:
SELECT COUNT(*) FROM dba_users;
COUNT(*)
----------
174