In method reduceExpressionsInternal, we get RexExecutor from cluster, it can be null: [image: image.png]
But in the outside(reduceExpressions), `final RexExecutor executor = Util.first(cluster.getPlanner().getExecutor(), RexUtil.EXECUTOR)`, it can't be null. And reduceExpressions is the only caller of reduceExpressionsInternal, so I think this is an inconsistent behavior. IMHO, we should create RexUtil.EXECUTOR if it is null in reduceExpressionsInternal, or just get RexExecutor from RexSimplify. [image: image.png] Regards! Aron Tao
