-476   REFERENCE TO FUNCTION function-name WAS NAMED WITHOUT A SIGNATURE, BUT THE FUNCTION IS NOT UNIQUE WITHIN ITS SCHEMA

References to a function without a signature are permitted, but the named function function-name must be unique in its schema and it is not.

Note also that in the ALTER FUNCTION, DROP FUNCTION, COMMENT ON FUNCTION, GRANT and REVOKE statements for EXECUTE on functions, an unqualified reference is qualified with the default schema, and this is the schema where the problem can be found. In the SOURCE clause of a CREATE FUNCTION statement, the qualification comes from the SQL path. In this case, the first schema in the path containing a function with this name had other functions by the same name.