Activating or Deactivating the Automatic Recreation of Damaged Indexes 
Prerequisites
You are logged on to the database as a database user.
You have the INDEX privilege for the table to which the damaged index belongs.
More information: SQL Reference Manual, Privilege Specification (privilege_specification)
The database is in the ONLINE operational state.
Procedure
Select the database in the explorer tree.
In the context menu of the database, choose
Administration Tasks 
Automatic Recreation of Bad Indexes 
.To deactivate this function, choose Deactivate automatic recreation of bad indexes.
To activate this function, choose Activate automatic recreation of bad indexes.