public static void unregisterPermanentFunction(String functionName) throws HiveException {
    system.unregisterFunction(functionName);
    unregisterTemporaryUDF(functionName);
  }
Registers the appropriate kind of temporary function based on a class's
type.

@param macroName name under which to register the macro

@param body the expression which the macro evaluates to
@param colNames the names of the arguments to the macro
@param colTypes the types of the arguments to the macro
ql/src/java/org/apache/hadoop/hive/ql/exec/FunctionRegistry.java