If you get the error How to fix ORA-01502: index or partition of such index is in usable state in Oracle. It is possible that an index is broken from a table.
When you get an error like: How to fix ORA-01654 unable to extend index in tablespace, then this article is for you!.
The problem in Oracle is that when you delete a record, Oracle will leave it blank. That’s a real waste of space when you delete thousands of records. So deleting records will not help to solve this problem.