name of the operator or function occupying the slot is not
   mentioned.  Also, for <code class="literal">DROP FUNCTION</code> the type(s) to specify
   are the input data type(s) the function is intended to support; for
   GiST, SP-GiST and GIN indexes this might have nothing to do with the actual
   input argument types of the function.
  </p><p>
   Because the index machinery does not check access permissions on functions
   before using them, including a function or operator in an operator family
   is 