[CALCITE-842] Decorrelator gets field offsets confused if fields have been trimmed

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.6.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 12/Aug/15 21:21
• Updated: 21/Jan/16 22:20
• Resolved: 11/Jan/16 04:55

Description

Decorrelator gets field offsets confused if fields have been trimmed. The query

select empno from "scott".emp as e
join "scott".dept as d using (deptno)
where e.sal in (
  select e2.sal from "scott".emp as e2 where e2.deptno > e.deptno);

gives the stack

Caused by: java.lang.NullPointerException
	at org.apache.calcite.sql2rel.RelDecorrelator.createValueGenerator(RelDecorrelator.java:746)
	at org.apache.calcite.sql2rel.RelDecorrelator.decorrelateInputWithValueGenerator(RelDecorrelator.java:856)
	at org.apache.calcite.sql2rel.RelDecorrelator.decorrelateRel(RelDecorrelator.java:915)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at org.apache.calcite.util.ReflectUtil.invokeVisitorInternal(ReflectUtil.java:256)
	at org.apache.calcite.util.ReflectUtil.invokeVisitor(ReflectUtil.java:213)
	at org.apache.calcite.util.ReflectUtil$1.invokeVisitor(ReflectUtil.java:476)
	at org.apache.calcite.sql2rel.RelDecorrelator$DecorrelateRelVisitor.visit(RelDecorrelator.java:1434)

The workaround is to disable trimming in SqlToRelConverter and do it only after sub-queries have been expanded and de-correlated. Search for references to this bug number introduced in the fix to CALCITE-816.

Issue Links

• is related to: CALCITE-816 Represent sub-query as a RexNode
• relates to: CALCITE-864 Correlation variable has incorrect row type if it is populated by right side of a Join