We must be very careful about breaking changes. We may want to put this change in Impala 3.0, rather than 2.x, if it breaks existing DDL statements.
> Field terminator can't be an empty string How is this different that the current restrictions on field terminators? If field terminators can currently be empty strings, what kind of queries or DDL statements does this break? Do we currently have tests for those? Do we expect that many users are using them? These questions are also of interest to me on your three other restrictions.
