A. When two-way disk mirroring is required for the allocation units
B. When three-way disk mirroring is required for the allocation units
C. When using hardware mirroring or RAID
D. When disk mirroring is required for the Automatic Storage Management (ASM) disks

A. It is effective only in partition pruning.
B. It is effective only in partitionwise joins provided that the query predicates are different from the partitioning key.
C. It is effective in both partition pruning as well as partitionwise joins provided that the query predicates are identical to the partitioning key.
D. It is effective in both partition pruning as well as partitionwise joins irrespective of whether the query predicates are different from or identical to the partitioning key.