[IMPALA-5206] NPE when "optimized" expression contains an aggregation

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Duplicate
• Affects Version/s: Impala 2.9.0
• Component/s: Frontend
• Labels: query_generator
• Target Version: Impala 2.9.0
• Epic Color: ghx-label-4
• Assignee: Thomas Tauber-Marshall
• Reporter: Michael Brown
• Created: 13/Apr/17 21:54
• Updated: 13/Apr/17 21:56
• Resolved: 13/Apr/17 21:56

Description

This seems similar to IMPALA-5125, but in this bug, we hit a Java NPE and error, not a DCHECK, so I think it's important to file this separately for now, since some path is different.

query:

EXPLAIN
SELECT IF(false, AVG(id), -1)
FROM functional.alltypestiny;

I0413 14:32:19.962172  9649 jni-util.cc:176] java.lang.NullPointerException
        at org.apache.impala.analysis.Analyzer.getEquivClasses(Analyzer.java:1781)
        at org.apache.impala.analysis.Analyzer.createEquivConjuncts(Analyzer.java:1744)
        at org.apache.impala.planner.AggregationNode.init(AggregationNode.java:147)
        at org.apache.impala.planner.SingleNodePlanner.createAggregationPlan(SingleNodePlanner.java:892)
        at org.apache.impala.planner.SingleNodePlanner.createSelectPlan(SingleNodePlanner.java:616)
        at org.apache.impala.planner.SingleNodePlanner.createQueryPlan(SingleNodePlanner.java:254)
        at org.apache.impala.planner.SingleNodePlanner.createSingleNodePlan(SingleNodePlanner.java:147)
        at org.apache.impala.planner.Planner.createPlan(Planner.java:87)
        at org.apache.impala.service.Frontend.createExecRequest(Frontend.java:1012)
        at org.apache.impala.service.Frontend.createExecRequest(Frontend.java:1103)
        at org.apache.impala.service.JniFrontend.createExecRequest(JniFrontend.java:155)

Just like with IMPALA-5125, using set enable_expr_rewrites=false is a workaround. Just like with IMPALA-5125, including GROUP BY looks OK.

twmarshall can you take the first look? I'm going under the assumption that this is a dupe of IMPALA-5125 based on RCA, or at least meta-similar. Again, though, different effect (no crash) means at least initially a separate bug. Thanks.