Select the index for maintaining in the object pane. Control-click and select the Maintain from the popup menu.
Rebuild Index
To re-create an existing index or one of its partitions or subpartitions. If the index is marked unusable, then a successful rebuild will mark it usable.
Make Index Unusable
To make the index unusable. An unusable index must be rebuilt, or dropped and re-created, before it can be used.
Coalesce Index
To instruct Oracle Database to merge the contents of index blocks where possible to free blocks for reuse.
Compute Index Statistics
To compute the statistics of the index.