又是8i的东西, 我发现自己真无知.
语法: alter index myindex unusable;
UNUSABLE Clause
Specify UNUSABLE to mark the index or index partition(s) or index subpartition(s) UNUSABLE. An unusable index must be rebuilt, or dropped and re-created, before it can be used. While one partition is marked UNUSABLE, the other partitions of the index are still valid. You can execute statements that require the index if the statements do not access the unusable partition. You can also split or rename the unusable partition before rebuilding it.
Restriction: You cannot specify this clause for an index on a temporary table.