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Progress Check Image

1. True or False: Tables with many foreign keys are good candidates for compression.

2. Name the two processing components involved in Oracle Database 10g's parallel processing.

3. What is the function of the SQLAccess Advisor?

4. True or False: In order to access the data in a materialized view, a user or application must query the materialized view directly?

5. List the ways in which parallel processing can be invoked.

6. In what situation can index key compression not be used on a unique index?

CRITICAL SKILL 9.6
Real Application Clusters: A Primer

When working with large databases, issues such as database availability, performance and scalability are very important. In today's 24/7 environments, it is not usually acceptable for a database to be unavailable for any length of time—even for planned maintenance or for coping with unexpected failures. Here's where Oracle Database 10g's Real Application Clusters (RAC) comes in.

Originally introduced in Oracle9i and only available with the Enterprise Edition, Real Application Clusters is a feature that allows database hardware and instances to be grouped together to act as one database using a shared-disk architecture. Following is a high-level discussion on RAC's architecture.

Progress Check Answers

1. True.

2. The Parallel Execution Coordinator and the Parallel Execution Servers.

3. The SQLAccess Advisor recommends potential materialized views based on historical or theoretical scenarios.

4. False. While the end user or application can query the materialized view directly, usually the target of a query is the detail data and Oracle's query rewrite capabilities will automatically return the results from the materialized view instead of the detail table (assuming the materialized view meets the query criteria).

5. Parallel processing can be invoked based on the parallelism specified for a table at the time of its creation, or by providing the parallel hint in a select query.

6. If the unique index has only one attribute, key compression cannot be used.

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0355-CRITICAL SKILL 9.6 Real Application Clusters: A Primer