Index &1 for InfoObject table &2 in metadata does not exist on database

What causes this issue?

An index that should be available according to SAP BW metadata does not
exist on the database.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Report an incident on component BW-SYS-DB-DB6.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.