Managing Optimizer Statistics

14 Managing Optimizer Statistics

14 掌握优化器统计信息

这一章将解释统计信息对于优化查询非常重要的原因以及如何使用dbms_stats包搜集统计信息。

本章包含以下部分内容：

 

This chapter explains why statistics are important for the queryoptimizer and how to gather and use optimizer statistics with the DBMS_STATS package.

The chapter contains the following sections:

• Understanding Statistics

• Automatic Statistics Gathering

• Manual Statistics Gathering

• System Statistics

• Managing Statistics

• Viewing Statistics