Which three statements are true with respect to has clusters? (Choose three)
A. Full table scans are generally faster on cluster tables than on non-clustered tables.
B. Hash clusters may be desirable when the number of key values is predictable and key values are evenly distributes.
C. If tables in a hash cluster require more space than the initial allocation for the cluster, performance degradation can be substantial because overflow blocks are required.
D. Storing a single table in a hash cluster can be useful regardless of whether the table is joined frequently with other tables or not, provided other criteria for choosing a hash cluster are met.
Answer: A, B, C
Explanation:
These statements are true with respect to clusters.
Incorrect Answers
D: Storing a single table in a hash cluster cannot be useful in some cases. It’s better to use clusters if table is joined frequently with other tables.
OCP: Oracle 9i Performance Tuning Study Guide, Joseph C. Johnson, p. 445-446
Chapter 8: Tuning Disk I/O
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