[CALCITE-1610] RelBuilder sort-combining optimization treats aliases incorrectly

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.11.0
• Fix Version/s: 1.12.0
• Component/s: core
• Assignee: Julian Hyde
• Reporter: Jess Balint
• Created: 27/Jan/17 21:55
• Updated: 24/Mar/17 03:20
• Resolved: 28/Jan/17 17:00

Description

This optimization in RelBuilder.sortLimit() manipulates the stack using replaceTop() which preserves the current field names. The current field names are not guaranteed to be the same as any descendant the Project and thus the replaceTop(sort2.getInput()) call places a RelNode on top of the stack with incorrect field names.

      if (top instanceof Project) {
        final Project project = (Project) top;
        if (project.getInput() instanceof Sort) {
          final Sort sort2 = (Sort) project.getInput();
          if (sort2.offset == null && sort2.fetch == null) {
            replaceTop(sort2.getInput());
            final RelNode sort =
                sortFactory.createSort(peek(), sort2.collation,
                    offsetNode, fetchNode);
            replaceTop(sort);
            project(project.getProjects());
            return this;
          }
        }
      }

Test:

    builder.scan("EMP")
           .sort(0)
           .project(builder.field(1))
           .limit(0, 1);

Throws:

java.lang.IndexOutOfBoundsException: index (1) must be less than size (1)
	at com.google.common.base.Preconditions.checkElementIndex(Preconditions.java:1177)
	at com.google.common.base.Preconditions.checkElementIndex(Preconditions.java:1159)
	at com.google.common.collect.SingletonImmutableList.get(SingletonImmutableList.java:41)
	at org.apache.calcite.tools.RelBuilder.inferAlias(RelBuilder.java:942)
	at org.apache.calcite.tools.RelBuilder.project(RelBuilder.java:869)
	at org.apache.calcite.tools.RelBuilder.project(RelBuilder.java:830)
	at org.apache.calcite.tools.RelBuilder.project(RelBuilder.java:819)
	at org.apache.calcite.tools.RelBuilder.sortLimit(RelBuilder.java:1549)
	at org.apache.calcite.tools.RelBuilder.limit(RelBuilder.java:1467)

Issue Links

• links to: PR#367