Stamatis et al, any additional feedback on desired features for such a change?
Thanks, Jacques On Mon, Dec 6, 2021 at 11:48 AM Julian Hyde <jhyde.apa...@gmail.com> wrote: > > > > On Dec 4, 2021, at 9:41 PM, Jacques Nadeau <jacq...@apache.org> wrote: > > > > A few thoughts: > > > > Algebra approach. > > > > > > If I understand the model correctly, I actually implemented this in a > > different project last year (not knowing it was now a design pattern). My > > main finding was that while it had certain benefits, it was pretty > > confusing for most people. > > Thanks, Vladimir, for educating us about the algebra approach. > > I have a feeling that OperandBuilder (used in the Config of many planner > rules) uses something like this pattern. I was not aware of the algebraic > approach, but OperandBuilder emerged as I tried to make the code type-safe > and reusable. > > The irony of the “algebra approach” is that Calcite is an algebra engine. > And a very powerful one at that. People who are new to Calcite often try to > use a visitor pattern on their RelNode tree, and we have to direct them to > the “algebra approach” of using collections of rewrite rules to accomplish > their task. > > For this reason, I think we should keep the built-in visitors fairly > simple. > > Also, my work in https://issues.apache.org/jira/browse/CALCITE-4559 < > https://issues.apache.org/jira/browse/CALCITE-4559> (not finished, sadly) > can be viewed as an attempt to convert RexSimplify (which is becoming > spaghetti code) into something more algebraic. > > Julian > > >
