RAC 11g has evolved into a mature, sophisticated, and optimized parallel architecture. In this section, we will look at what makes RAC superior to previous Oracle parallel database solutions and single-instance databases in the context of performance tuning. Normal database monitoring is covered thoroughly in any number of other texts. Thus, aspects of database tuning such as SQL tuning or standard SGA and internals tuning are not covered in this chapter, other than the required extensions to normal database monitoring relevant to Oracle RAC databases.
The essential difference between an RAC cluster and a non-RAC Oracle database is very simple—RAC introduces the concept of Cache Fusion. Since the introduction of Cache Fusion, it has been enhanced with many new features, which make it faster than OPS due to the ability for instant block transfer between instances via the private interconnect and with reduced messaging...