SQL GroupBy query fails for aggregations returning complex type

[samarthjain]

Affected Version

master

Description

I have been working on adding SQL support for T-Digest sketches and ran into an issue for group by queries that project aggregations returning a complex type.

For ex - the below query fails for bloom filter aggregators.
SELECT BLOOM_FILTER(l1, 1000) FROM numfoo group by dim2

`java.lang.RuntimeException: Error while applying rule DruidQueryRule(AGGREGATE_PROJECT), args [rel#26:LogicalProject.NONE., rel#33:DruidQueryRel.NONE.[](query={"queryType":"groupBy","dataSource":{"type":"table","name":"numfoo"},"intervals":{"type":"intervals","intervals":["-146136543-09-08T08:23:32.096Z/146140482-04-24T15:36:27.903Z"]},"virtualColumns":[],"filter":null,"granularity":{"type":"all"},"dimensions":[{"type":"default","dimension":"dim2","outputName":"_d0","outputType":"STRING"}],"aggregations":[{"type":"bloom","name":"a0:agg","field":{"type":"default","dimension":"dim1","outputName":"a0:dim1","outputType":"STRING"},"maxNumEntries":1000}],"postAggregations":[],"having":null,"limitSpec":{"type":"NoopLimitSpec"},"context":{"defaultTimeout":300000,"maxScatterGatherBytes":9223372036854775807,"sqlCurrentTimestamp":"2000-01-01T00:00:00Z","sqlQueryId":"dummy"},"descending":false},signature={_d0:STRING, a0:agg:COMPLEX})]

at org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:236)
at org.apache.calcite.plan.volcano.VolcanoPlanner.findBestExp(VolcanoPlanner.java:646)
at org.apache.calcite.tools.Programs$RuleSetProgram.run(Programs.java:339)
at org.apache.calcite.tools.Programs$SequenceProgram.run(Programs.java:358)
at org.apache.calcite.prepare.PlannerImpl.transform(PlannerImpl.java:337)
at org.apache.druid.sql.calcite.planner.DruidPlanner.planWithDruidConvention(DruidPlanner.java:119)
at org.apache.druid.sql.calcite.planner.DruidPlanner.plan(DruidPlanner.java:89)
at org.apache.druid.sql.SqlLifecycle.plan(SqlLifecycle.java:141)
at org.apache.druid.sql.SqlLifecycle.planAndAuthorize(SqlLifecycle.java:207)
at org.apache.druid.sql.SqlLifecycle.runSimple(SqlLifecycle.java:244)
at org.apache.druid.query.aggregation.bloom.sql.BloomFilterSqlAggregatorTest.testBloomFilterAgg(BloomFilterSqlAggregatorTest.java:230)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.apache.druid.sql.calcite.util.QueryLogHook$1.evaluate(QueryLogHook.java:95)
at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Caused by: org.apache.druid.java.util.common.ISE: No ExprType for valueType[COMPLEX]
at org.apache.druid.sql.calcite.expression.Expressions.exprTypeForValueType(Expressions.java:576)
at org.apache.druid.sql.calcite.rel.Projection.postAggregatorDirectColumnIsOk(Projection.java:197)
at org.apache.druid.sql.calcite.rel.Projection.postAggregation(Projection.java:108)
at org.apache.druid.sql.calcite.rel.DruidQuery.computeGrouping(DruidQuery.java:313)
at org.apache.druid.sql.calcite.rel.DruidQuery.(DruidQuery.java:167)
at org.apache.druid.sql.calcite.rel.PartialDruidQuery.build(PartialDruidQuery.java:306)
at org.apache.druid.sql.calcite.rel.DruidQueryRel.toDruidQuery(DruidQueryRel.java:97)
at org.apache.druid.sql.calcite.rel.DruidQueryRel.toDruidQueryForExplaining(DruidQueryRel.java:109)
at org.apache.druid.sql.calcite.rel.DruidRel.isValidDruidQuery(DruidRel.java:62)
at org.apache.druid.sql.calcite.rule.DruidRules$DruidQueryRule.onMatch(DruidRules.java:132)
at org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:212)
... 39 more`

[gianm]

I think it would probably be fine to just return true from Projection.postAggregatorDirectColumnIsOk if it's a direct column access and the column type in aggregateRowSignature is COMPLEX. The point of the method is to determine if a field can be read without an implicit cast, and there aren't any implicit casts for complex types anyway, so why not go ahead.