Which are two characteristics of “invisible” index functionality that would help tune a database having
thousands of legacy indexes?
A. An invisible index is ignored by the optimizer.
B. After an index becomes invisible, it is no longer maintained during inserts and updates.
C. I/O bottlenecks are easy to spot when invisible indexes are used.
D. An index only needs to be rebuilt for it to be visible again.
E. The session or system parameter needs to be changed to OPTIMIZER_USE_INVISIBLE_INDEXES to
TRUE for an invisible index to become visible to the Optimizer.