Github user Ben-Zvi commented on the issue:
https://github.com/apache/drill/pull/536
The work in this PR is dated; the relevant base code has changed so much
(e.g. DRILL-5547, DRILL-5752) so this change cannot just be pulled; it needs to
be redone. Also part of the intended goal is now covered by DRILL-5723, which
separated the internal options out of sys.options, thus allowing to hide those
options that users "should not modify". ---
