Hi Tugdual, The only reason for removing _id field from select * is, in most of the cases value of _id field generated by Mongo system and users normally do not use. However, if users select _id field (cases where users using _id as key) drill returns its value.
On Thu, Jul 16, 2015 at 5:53 PM, Tugdual Grall <[email protected]> wrote: > Hello, > > I would like to push down the ORDER BY to the MongoDB database itself ( see > https://issues.apache.org/jira/browse/DRILL-3165 ) > > I have looked into the Optimizer, Record Reader and Scan, I do not see how > I can get the "Order by" clause information from the context. > > I see how the filters and projection are used. > > Any clue? > > > PS: another side question about Projection & MongoDB: > Any reason why the _id is by default removed from the "select * from > collection" ? > > > > Regards > Tug > @tgrall > -- Kamesh.
