I submitted a pull request to Julian today for the option parsing in optiq
and he already pulled it in, so I was going to finish up connecting drill
to it. Previously I was converting the rel node for setting options into a
new Drill operator. This has been replaced with specifying the options in
the plan header, with the options being read and set in the foreman when
the query is submitted.
For options provided though SQL, I believe that single query strings can
only contain a single option setting statement and nothing else. This would
leave us with an empty plan, but meaningful headers. Do we want to define a
different type of message for these and other possible non-query messages
passed to Drill? I haven't checked to see it the current plan reader will
accept an empty plan graph, but I wanted to confirm if this would be a
reasonable way to do it.