Calcite query planning error

    org.apache.calcite.plan.RelOptPlanner$CannotPlanException: Node [rel#16:Subset#2.LOGICAL.[]] could not be implemented; planner state:

    Root: rel#16:Subset#2.LOGICAL.[]
    Original rel:

    Sets:
    Set#0, type: RecordType(INTEGER id, VARCHAR(10) productId, INTEGER units, TIMESTAMP(0) rowtime)
    	rel#11:Subset#0.NONE.[], best=null, importance=0.7290000000000001
    		rel#3:LogicalTableScan.NONE.[](table=[KAFKA, ORDERS]), rowcount=100.0, cumulative cost={inf}
    Set#1, type: RecordType(VARCHAR(10) productId, INTEGER units)
    	rel#13:Subset#1.NONE.[], best=null, importance=0.81
    		rel#12:LogicalProject.NONE.[](input=rel#11:Subset#0.NONE.[],productId=$1,units=$2), rowcount=100.0, cumulative cost={inf}
    Set#2, type: RecordType(VARCHAR(10) productId, INTEGER units)
    	rel#15:Subset#2.NONE.[], best=null, importance=0.9
    		rel#14:LogicalDelta.NONE.[](input=rel#13:Subset#1.NONE.[]), rowcount=100.0, cumulative cost={inf}
    		rel#21:LogicalProject.NONE.[](input=rel#20:Subset#3.NONE.[],productId=$1,units=$2), rowcount=100.0, cumulative cost={inf}
    	rel#16:Subset#2.LOGICAL.[], best=null, importance=1.0
    		rel#17:AbstractConverter.LOGICAL.[](input=rel#15:Subset#2.NONE.[],convention=LOGICAL,sort=[]), rowcount=100.0, cumulative cost={inf}
    Set#3, type: RecordType(INTEGER id, VARCHAR(10) productId, INTEGER units, TIMESTAMP(0) rowtime)
    	rel#20:Subset#3.NONE.[], best=null, importance=0.81
    		rel#18:LogicalDelta.NONE.[](input=rel#11:Subset#0.NONE.[]), rowcount=100.0, cumulative cost={inf}
    		rel#22:LogicalTableScan.NONE.[[3]](table=[]), rowcount=100.0, cumulative cost={inf}
    	rel#23:Subset#3.NONE.[3], best=null, importance=0.405
    		rel#22:LogicalTableScan.NONE.[[3]](table=[]), rowcount=100.0, cumulative cost={inf}
        at org.apache.calcite.plan.volcano.RelSubset$CheapestPlanReplacer.visit(RelSubset.java:473)
        at org.apache.calcite.plan.volcano.RelSubset.buildCheapestPlan(RelSubset.java:317)
        at org.apache.calcite.plan.volcano.VolcanoPlanner.findBestExp(VolcanoPlanner.java:823)
        at org.apache.calcite.tools.Programs$RuleSetProgram.run(Programs.java:303)
        at org.apache.calcite.prepare.PlannerImpl.transform(PlannerImpl.java:268)
        at org.apache.samza.sql.planner.QueryPlanner.convertToSamzaRel(QueryPlanner.java:115)
        at org.apache.samza.sql.planner.QueryPlanner.validateAndConvert(QueryPlanner.java:109)
        at org.apache.samza.sql.planner.QueryPlanner.getPlan(QueryPlanner.java:98)
        at org.apache.samza.sql.planner.TestQueryPlanner.testSimpleProject(TestQueryPlanner.java:108)

Hey Milinda,

I know I am (3 years) late to the party, but, will still take my chances ...

Were you able to resolve this error? If yes, how? I am trying to do something similar, where I combine 2 plans (RelNode) using a LogicalUnion and then try to optimize the plan using RelOptPlanner.findBestExp and run into a similar error. Quick gist of what I am doing

RelBuilder relBuilder = ...
RelNode a = ...
RelNode b = ...
RelNode union = relBuilder.union(true)
RelOptPlanner planner = union.getCluster().getPlanner()
planner.setRoot(union)
RelNode optimizedPlan = planner.findBestExp()

This gives an error very similar to the one in your gist.

Thanks,
Prakhar