Cause
The index was not in a valid state due to some prior error.
The index was not in a valid state due to some prior error.
Drop index and create index again.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/drgus.htm
https://community.oracle.com/message/9974009
https://community.oracle.com/message/9745204
https://community.oracle.com/message/9912083
https://community.oracle.com/message/11001724
https://community.oracle.com/message/9476252
https://community.oracle.com/message/9915597
https://community.oracle.com/message/11317211
https://community.oracle.com/message/9902810
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