读书 《Oracle Wait Interface: A Practical Guide to Performance Diagnostics & Tuning》

花了将近一个月的时间，看完了电子版的《Oracle Wait Interface: A Practical Guide to Performance Diagnostics & Tuning》

目录：

Chapter 1 - Introduction to Oracle Wait Interface

简单介绍，最后给了一个总结：

Using OWI, DBAs can precisely identify the major bottlenecks in the system based on time and resolve performance issues by applying the appropriate solution that reduces or bypasses the bottlenecks.

Chapter 2 - Oracle Wait Interface Components

介绍组件，最后列出几点不足：

No CPU Statistics

No End-to-End Visibility

No Historical Data

Inaccuracies

Chapter 3 - Common Wait Events

介绍了23个常见的等待事件。还有9个RAC相关的。

最后是“row cache lock”。

The dictionary cache is known as row cache because it keeps the information at row level, as opposed to the buffer cache, which keeps the information at block level. The locks, which protect the definition of the data dictionary objects, are called row cache
locks. Normally, DDL statements require row cache lock, and the session will wait for the row cache lock to lock the data dictionary information.

Chapter 4 - OWI Monitoring and Collection Methods

提出一个问题：

A question from a customer such as, “Why did the job run so slowly?” is not only a loaded question, it has to be the most challenging question a DBA can face.

然后给出了数据收集的几个建议

Wait-based methodology

Session-level granularity

Always-on and low overhead

Historical repositories

又给出了用PL/SQL来收集的例子。等有空的时候，一定试试。

Chapter 5 - Interpreting Common I/O Related Wait Events

Chapter 6 - Interpreting Locks-Related Wait Events

Chapter 7 - Interpreting Common Latency-Related Wait Events

Chapter 8 - Wait Events in a Real Application Clusters Environment

Chapter 9 - Performance Management in Oracle Database 10g

还有附录A也很不错。

Appendix A - Oracle Database 10g Diagnostic Events

Events in Oracle can be broadly classified into two groups: wait events and diagnostic events.

Oracle diagnostic events can be classified in four major categories based on their usage as discussed in the following sections.

Immediate Dump Events，比如：

alter session set events 'immediate trace name controlf level 10';

On Error Dump Events

Change Behavior Events

Process Trace Events，比如：

SQL> alter session set events '10046 trace name context forever, level 1';