[From Oracle Technology Network
With the new and enhanced wait interfaces built into the Oracle kernel, DBAs who choose to explore beyond 10g's performance-tuning recommendations should be able to more quickly get to the bottom of performance issues
In the pursuit of optimal database performance, Oracle professionals have been slowly migrating away from performance analysis techniques that focused on blanket system ratios to a methodology that instead zeros in on where a system, application, or session is spending its time. Referred to as wait-based analysis or bottleneck analysis, its goal is to uncover the true nature of performance degradation by determining the exact causes of throughput hindrances.
The wait interface of Oracle was introduced many versions ago, and with each new release, Oracle has added enhancements to the wait interface that helps DBAs better understand where database bottlenecks are occurring. Oracle Database 10g is no exception, and in fact, it offers perhaps the most impressive set of new additions to the wait interface ever. 10g also provides a new built-in diagnostic monitor (ADDM) and other tools that survey, among other things, how wait events affect SQL performance and more.
The article continues at