Note:Stored outlines will be desupported in a future release in favor of SQL plan management. In Oracle Database 11g Release 2 (11.2), stored outlines continue to function as in past releases. Oracle strongly recommends that you use SQL plan management for new applications. SQL plan management creates SQL plan baselines, which offer superior SQL performance stability compared with stored outlines.
You can migrate existing stored outlines to SQL plan baselines by using the
MIGRATE_STORED_OUTLINE function of the
DBMS_SPM package or Enterprise Manager DB Control. When the migration is complete, the stored outlines are marked as migrated and can be removed. You can drop all migrated stored outlines on your system by using the
DROP_MIGRATED_STORED_OUTLINE function of the
See Also: Oracle Database Performance Tuning Guide for more information about SQL plan management and Oracle Database PL/SQL Packages and Types Reference for information about the
OUTLINE statement to create a stored outline, which is a set of attributes used by the optimizer to generate an execution plan. You can then instruct the optimizer to use a set of outlines to influence the generation of execution plans whenever a particular SQL statement is issued, regardless of changes in factors that can affect optimization. You can also modify an outline so that it takes into account changes in these factors.
Note:The SQL statement you want to affect must be an exact string match of the statement specified when creating the outline.
To create a public or private outline, you must have the
OUTLINE system privilege.
If you are creating a clone outline from a source outline, then you must also have the
USE_STORED_OUTLINES parameter to use public outlines.
USE_PRIVATE_OUTLINES parameter to use private stored outlines.
See Also:Oracle Database Performance Tuning Guide for information on using outlines for performance tuning
Note:None of the clauses after
outlineare required. However, you must specify at least one clause after
outline, and it must be either the
FROMclause or the
REPLACE to replace an existing outline with a new outline of the same name.
PUBLIC if you are creating an outline for use by
PUBLIC. This is the default.
PRIVATE to create an outline for private use by the current session only. The data of this outline is stored in the current schema.
Specify the unique name to be assigned to the stored outline. If you do not specify
outline, then the database generates an outline name.
See Also:"Creating an Outline: Example"
FROM clause to create a new outline by copying an existing one. By default, Oracle Database looks for
source_category in the public area. If you specify
PRIVATE, then the database looks for the outline in the current schema.
See Also:"Creating a Private Clone Outline: Example" and "Publicizing a Private Outline to the Public Area: Example"
Specify an optional name used to group stored outlines. For example, you could specify a category of outlines for end-of-week use and another for end-of-quarter use. If you do not specify
category, then the outline is stored in the
Specify the SQL statement for which the database will create an outline when the statement is compiled. This clause is optional only if you are creating a copy of an existing outline using the
You can specify any one of the following statements:
If you specify the
ON clause, then you cannot specify the
You cannot create an outline on a multitable
The SQL statement in the
ON clause cannot include any DML operation on a remote object.
Note:In subsequent statements, you can specify additional outlines for the same SQL statement, but each outline for the same statement must specify a different category in the
CREATE OUTLINE salaries FOR CATEGORY special ON SELECT last_name, salary FROM employees;
When this same
SELECT statement is subsequently compiled, if the
USE_STORED_OUTLINES parameter is set to
special, the database generates the same execution plan as was generated when the outline
salaries was created.
CREATE OR REPLACE PRIVATE OUTLINE my_salaries FROM salaries;
CREATE OR REPLACE OUTLINE public_salaries FROM PRIVATE my_salaries;