Oracle Database - Hints

Card Puncher Data Processing

About

You can use hints to alter the execution path chosen by the cost-based optimizer. Hints are embedded within SQL statements, and only modify the execution path for the statements in which they appear. A hint follows a SELECT, INSERT, UPDATE, or DELETE keyword in the respective statements. The following string indicates the start of a hint:

/*+

The following string indicates the end of a hint:

*/

The syntax for hints is almost identical to that of comments within SQL. The only difference is the addition of the + sign to indicate the start of the hint. The + cannot be preceded by a space.

When a hint is specified incorrectly, the optimizer ignores it and does not report an error. Many of the hints allow you to list specific table names. When you use table aliases in your query, refer to the tables by their aliases within the hints.

DRIVING_SITE

A distributed DML statement must execute on the database where the DML target resides. The DRIVING_SITE hint cannot override this.

Metadata

select * from v$sql_hint

Documentation / Reference





Discover More
Bi Server Architecture With Client
OBIEE - Hint

Database hints are instructions placed within a SQL statement that tell the database query optimizer the most efficient way to execute the statement. Hints override the optimizer’s execution plan,...
Owb Table Operator Data Rule Properties
OWB - Table

The Table operator enables you to source data from and load data into tables stored You can set Target Filter for Update, Target Filter for Delete, and Match By Constraint. When a data...
Card Puncher Data Processing
Oracle Database

Documentation about the Oracle database
Card Puncher Data Processing
Oracle Database - Data Loading Hint

The PL/SQL data loading procedures use the following HINTS for performance. They are /+ APPEND NOLOGGING PARALLEL / Append: - When “Append” hint is used in a PL/SQL INSERT statement, Oracle will...
Card Puncher Data Processing
Oracle Database - FIRST_ROWS

FIRST_ROWS is an optimizer goal in order to ask it the best response time. You can instruct this instruction through: a hint or by setting the value of the optimizer goal In the two case, it instructs...
Card Puncher Data Processing
Oracle Database - Full Table Scans

in Oracle During a full table scan, all blocks in the table that are under the high water mark are scanned. Each row is examined to determine whether it satisfies the statement's WHERE clause. When Oracle...
Card Puncher Data Processing
Oracle Database - Hash joins

Hash Join The optimizer uses a hash join to join two tables if they are joined using an equijoin and if either of the following conditions are true: A large amount of data needs to be joined. ...
Card Puncher Data Processing
Oracle Database - How to (enable|disable) parallel query and get (degree of parallelism|DOP) ?

How to enable a parallel execution: for a for a operation Small tables/indexes (up to thousands of records; up to 10s of data blocks) should never be enabled for parallel execution. Operations...
Card Puncher Data Processing
Oracle Database - Index Scans

The Index Scans is a access path used by the query optimizer to produce the best . In this method, a row is retrieved by traversing the index, using the indexed column values specified by the statement....
Card Puncher Data Processing
Oracle Database - Optimizer Goal (CBO/RBO)

in Oracle In Oracle 9i and before the query plan generated by the Oracle database were determined by certain rules In 10g and above, it is based on The OPTIMIZER_MODE initialization parameter...



Share this page:
Follow us:
Task Runner