Oracle___專題研究__Oracle預設使用者

A newly created database has least three users that are useful for administering
your database: SYS, SYSTEM and OUTLN (owner of schema where stored outlines
are stored).
Depending on the features and options installed, other users can also be present.
Some of these users are:
n MDSYS (interMedia Spatial)
n ORDSYS (interMedia Audio)
n ORDPLUGINS (interMedia Audio)
n CTXSYS (Oracle Text)
n DBSNMP (Enterprise Manager Intelligent Agent)
Caution: To prevent unauthorized access and protect the integrity
of your database, the default passwords for SYS and SYSTEM
should be changed immediately after the database is created.

關於outln:

是最佳化方面的一個東西
After carefully tuning an application, you might want to ensure that the optimizer generates the same execution plan whenever the same SQL statements are executed. Plan stability allows you to maintain the same execution plans for the same SQL statements, regardless of changes to the database such as re-analyzing tables, adding or deleting data, modifying a table's columns, constraints, or indexes, changing the system configuration, or even upgrading to a new version of the optimizer.

The CREATE OUTLINE statement creates a stored outline, which contains a set of attributes that the optimizer uses to create an execution plan. Stored outlines can also be created automatically by setting the system parameter CREATE_STORED_OUTLINES to TRUE.

The system parameter USE_STORED_OUTLINES can be set to TRUE, FALSE, or a category name to indicate whether to make use of existing stored outlines for queries that are being executed. The OUTLN_PKG package provides procedures used for managing stored outlines.

Implementing plan stability creates a new schema called OUTLN, which is created with DBA privileges. The database administrator should change the password for the OUTLN schema just as for the SYS and SYSTEM schemas.

see(oracle817):
c0800050.sql and dbmsol.sql