This feature could be
used to automatically switch a consumer group oriented toward short OLTP operations
to another group that would be more appropriate for batch operations.
Since Oracle Database 10g, you can define a consumer group by the service name,
application, host machine, or operating system username of a user.
Real Application Clusters
Arguably, the biggest advance in Oracle9i was a feature called Real Application Clusters.
Real Application Clusters (RAC) was a new version of technology replacing
Oracle Parallel Server (OPS).
In the first edition of this book, we described OPS as a feature that could be used for
improving performance and scalability for certain data warehouse-style applications??”
applications in which data could be partitioned in logical ways and applications that
primarily supported read activity. The reason why use of OPS was mostly limited to
data warehousing implementations was the phenomenon known as pinging.
216 | Chapter 9: Oracle and Transaction Processing
In the world of both OPS and RAC, multiple machines access the same database files
on shared disk (either physically attached or appearing as physically attached
through software), as shown in Figure 9-6.
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