Hi Ian, Is there any specific reason or use case that you have to match the root node and find the parent node in your customized rule?
Thanks, Haisheng Yuan On 2021/05/03 20:20:22, Julian Hyde <jh...@apache.org> wrote: > > Is there a way to identify a node as being a root node during RelRule.match? > > Not currently. One workaround would be to create 'class MyRoot extends > SingleRel', add it as the root of the tree, and write your rules to > match on it. > > > Or more generally, is there a way to collect the parents of an arbitrary > > RelNode? > > By design, the only way to find the parents of a RelNode are to write > a rule that matches those parents. This ensures that rules will work > in the Volcano planner, where a RelNode can have many parents. > > Julian > > On Mon, May 3, 2021 at 12:52 PM Ian Bertolacci > <ian.bertola...@workday.com.invalid> wrote: > > > > Hello, > > I am trying to write a rule that matches (among other things) the root of a > > RelNode tree. > > > > Unfortunately, it seems that HepRuleCall.parents is only initialized and > > populated if the rule extends CommonRelSubExpr, which doesn’t really apply > > in my case. > > (see: > > https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/plan/hep/HepPlanner.java#L526) > > > > Is there a way to identify a node as being a root node during > > RelRule.match? Or more generally, is there a way to collect the parents of > > an arbitrary RelNode? > > > > Thanks. >
