2012-12-17 11gR2 "Performance Tuning Guide" page 1 - 49

Oracle Database 11g Release 2 (11.2.0.2) New Features in Oracle

Database Performance -- 11202新特性

Oracle Orion I/O Calibration Tool Documentation -- Oracle Orion I/O测试工具

Oracle Orion is a tool for predicting the performance of an Oracle database

without having to install Oracle or create a database. Unlike other I/O calibration

tools, Oracle Orion is expressly designed for simulating Oracle database I/O

workloads using the same I/O software stack as Oracle. Orion can also simulate

the effect of striping performed by Oracle Automatic Storage Management.

The Symptoms and the Problems -- 性能问题的征兆

-- Slow physical I/O -- IO缓慢

Generally, this is caused by poorly-configured disks. However, it could also be

caused by a significant amount of unnecessary physical I/O on those disks issued

by poorly-tuned SQL.

-- Latch contention -- 闩的争用

Rarely is latch contention tunable by reconfiguring the instance. Rather, latch

contention usually is resolved through application changes.

-- Excessive CPU usage -- CPU的过度使用

Excessive CPU usage usually means that there is little idle CPU on the system.

This could be caused by an inadequately-sized system, by untuned SQL

statements, or by inefficient application programs.