Optimizer with Oracle Database 12c Release 2 (White Paper)

Oracle White Paper
Optimizer with Oracle Database 12c Release 2

Introduction

The Oracle Optimizer is one of the most fascinating components of the Oracle Database, since it is essential to the processing of every SQL statement. The optimizer determines the most efficient execution plan for each SQL statement based on the structure of the given query, the available statistical information about the underlying objects, and all the relevant optimizer and execution features.
This paper introduces all of the new optimizer and statistics related features in Oracle Database 12c Release 21 and provides simple, reproducible examples to make it easier to get acquainted with them, especially when migrating from previous versions. It also outlines how existing functionality has been enhanced to improve both performance and manageability.
Some Oracle Optimizer features have been broken out of this paper and covered in their own. Specifically, they are:

» Optimizer Statistics and Optimizer Statistics Advisor
» SQL Plan Management
» Approximate Query Processing

http://www.oracle.com/technetwork/database/bi-datawarehousing/twp-optimizer-with-oracledb-12c-1963236.pdf