Index reorganization is essential for volatile indexes because? (Choose three.)
A. Deleted row entries are reused based on index key value.
B . Deleted row entries are reused based on the PCTUSED block parameter.
C. Delete activity will degrade the index performance.
D. Leaf blocks with only one entry are still maintained.
E . Modified index keys are moved to less sparse blocks.
Explanation:
Answer A, C and D: Compared to an index with no empty row slots, an index with deleted rows will have an overall reduction in effectiveness because more block reads will be required to process the same number of rows. When a row is deleted, a new entry into the index will only replace it if the index key value is identical; therefore, there is a the potential that deleted row entries will not be reused. Each block in the index is maintained, even if there is only one row in it.
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