[CALCITE-566] ReduceExpressionsRule requires planner to have an Executor

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.1.0-incubating
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 25/Jan/15 05:16
• Updated: 23/Mar/15 08:08
• Resolved: 06/Mar/15 08:13

Description

ReduceExpressionsRule requires planner to have an Executor. If it does not, you get a stack trace like this:

java.lang.NullPointerException
	at org.apache.calcite.rel.rules.ReduceExpressionsRule.reduceExpressions(ReduceExpressionsRule.java:387)
	at org.apache.calcite.rel.rules.ReduceExpressionsRule$3.onMatch(ReduceExpressionsRule.java:223)
	at org.apache.calcite.plan.AbstractRelOptPlanner.fireRule(AbstractRelOptPlanner.java:326)
	at org.apache.calcite.plan.hep.HepPlanner.applyRule(HepPlanner.java:515)
	at org.apache.calcite.plan.hep.HepPlanner.applyRules(HepPlanner.java:393)
	at org.apache.calcite.plan.hep.HepPlanner.executeInstruction(HepPlanner.java:285)
	at org.apache.calcite.plan.hep.HepInstruction$RuleCollection.execute(HepInstruction.java:72)
	at org.apache.calcite.plan.hep.HepPlanner.executeProgram(HepPlanner.java:207)
	at org.apache.calcite.plan.hep.HepPlanner.findBestExp(HepPlanner.java:194)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner$CalcitePlannerAction.hepPlan(CalcitePlanner.java:837)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner$CalcitePlannerAction.applyPreJoinOrderingTransforms(CalcitePlanner.java:770)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner$CalcitePlannerAction.apply(CalcitePlanner.java:701)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner$CalcitePlannerAction.apply(CalcitePlanner.java:658)
	at org.apache.calcite.tools.Frameworks$1.apply(Frameworks.java:109)
	at org.apache.calcite.prepare.CalcitePrepareImpl.perform(CalcitePrepareImpl.java:715)
	at org.apache.calcite.tools.Frameworks.withPrepare(Frameworks.java:145)
	at org.apache.calcite.tools.Frameworks.withPlanner(Frameworks.java:105)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner.getOptimizedAST(CalcitePlanner.java:568)
	at org.apache.hadoop.hive.ql.parse.CalcitePlanner.genOPTree(CalcitePlanner.java:224)

There is a workaround. Set the executor of the planner before invoking findBestExp. Set it on the planner of the cluster of the root RelNode (which is not necessarily the planner that is executing the rules):

final RexExecutorImpl executor =
    new RexExecutorImpl(Schemas.createDataContext(null));
rootRel.getCluster().getPlanner().setExecutor(executor);

We should fix this by having the rule give a warning and return (doing nothing) if an executor is not set.