[CALCITE-3353] ProjectJoinTransposeRule caused AssertionError when creating a new Join

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.20.0
• Fix Version/s: 1.22.0
• Component/s: core
• Labels: pull-request-available
• Assignee: TANG Wen-hui
• Reporter: TANG Wen-hui
• Created: 17/Sep/19 13:12
• Updated: 06/Mar/20 04:34
• Resolved: 30/Nov/19 08:28

Description

Trying to add ProjectJoinTransposeRule to the rule set to optimize sql (using VolcanoPlanner).

Get the following exception：

Caused by: java.lang.AssertionErrorCaused by: java.lang.AssertionError at org.apache.calcite.adapter.enumerable.EnumerableMergeJoin.<init>(EnumerableMergeJoin.java:72) at org.apache.calcite.adapter.enumerable.EnumerableMergeJoin.copy(EnumerableMergeJoin.java:112) at org.apache.calcite.adapter.enumerable.EnumerableMergeJoin.copy(EnumerableMergeJoin.java:59) at org.apache.calcite.rel.rules.ProjectJoinTransposeRule.onMatch(ProjectJoinTransposeRule.java:155) at org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:208) at org.apache.calcite.plan.volcano.VolcanoPlanner.findBestExp(VolcanoPlanner.java:703) at org.apache.calcite.tools.Programs.lambda$standard$7(Programs.java:466) at org.apache.calcite.tools.Programs$SequenceProgram.run(Programs.java:528) at org.apache.calcite.prepare.Prepare.optimize(Prepare.java:196) at org.apache.calcite.prepare.Prepare.prepareSql(Prepare.java:416) at org.apache.calcite.prepare.Prepare.prepareSql(Prepare.java:310) at org.apache.calcite.prepare.CalcitePrepareImpl.prepare2_(CalcitePrepareImpl.java:830) at org.apache.calcite.prepare.CalcitePrepareImpl.prepare_(CalcitePrepareImpl.java:610) at org.apache.calcite.prepare.CalcitePrepareImpl.prepareSql(CalcitePrepareImpl.java:580) at org.apache.calcite.jdbc.CalciteConnectionImpl.parseQuery(CalciteConnectionImpl.java:247) at org.apache.calcite.jdbc.CalciteMetaImpl.prepareAndExecute(CalciteMetaImpl.java:711)
... 22 more

This is because the ProjectJoinTransposeRule can match multiple types of Join and ProjectJoinTransposeRule creates a new Join using the join.copy() method. When the rule applied to EnumerableMergeJoin, and the new Join created by this rule may not meet the requirements of EnumerableMergeJoin.

  EnumerableMergeJoin(
      RelOptCluster cluster,
      RelTraitSet traits,
      RelNode left,
      RelNode right,
      RexNode condition,
      Set<CorrelationId> variablesSet,
      JoinRelType joinType) {
    super(cluster, traits, left, right, condition, variablesSet, joinType);
    final List<RelCollation> collations =
        traits.getTraits(RelCollationTraitDef.INSTANCE);
    assert collations == null || RelCollations.contains(collations, joinInfo.leftKeys);
  }

Issue Links

• links to: GitHub Pull Request #1462