I think you’re talking about SQL hints. It’s a feature that has been talked about several times but has never been implemented. See https://issues.apache.org/jira/browse/CALCITE-482 <https://issues.apache.org/jira/browse/CALCITE-482>.
The full feature would require (1) extension to the parser to read hints, (2) a way of annotating RelNodes with hints, (3) changes to SqlToRelConverter propagate hints from the parse tree to the RelNode tree, but I think you need just (2). I’ll add some remarks on the JIRA case, and let’s discuss further there. Julian > On Jul 6, 2017, at 7:53 AM, Renaud Delbru <[email protected]> wrote: > > Hi, > > When creating a logical tree from our parse tree, we would like to be able > to attach metadata information to the logical rel node. For example, a user > could specify a particular algo to use for a join (e.g., hash join, merge > join, etc.), and we would need to attach this information to the > LogicalJoin node in order to have access to it when creating the physical > tree. What would be the correct approach to do that ? Are there examples > available somewhere that we can look at for inspiration ? > > Thanks > Kind Regards > > -- > *Renaud Delbru* Siren Solutions - CTO > T +353 91704885 | > [email protected] | http://siren.solutions/ > Unit 13 GTC, Mervue Park, Galway, Ireland
