[IMPALA-9945] Subquery inside some Expr subclasses in WHERE results in IllegalStateException

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Frontend
• Labels: newbie ramp-up
• Epic Link: Subquery Support
• Epic Color: ghx-label-5
• Assignee: Unassigned
• Reporter: Tim Armstrong
• Created: 10/Jul/20 15:53
• Updated: 10/Jul/20 23:36

Description

[localhost.EXAMPLE.COM:21000] default> explain select * from functional.alltypes t
where nvl(exists(select id from functional.alltypesagg), false);
Query: explain select * from functional.alltypes t
where nvl(exists(select id from functional.alltypesagg), false)
ERROR: IllegalStateException: Failed analysis after expr substitution.
CAUSED BY: ClassCastException: org.apache.impala.analysis.SlotRef cannot be cast to org.apache.impala.analysis.Subquery

[localhost.EXAMPLE.COM:21000] default> explain select * from functional.alltypes t
where case when id % 2 = 0 then exists(select id from functional.alltypesagg) end;
Query: explain select * from functional.alltypes t
where case when id % 2 = 0 then exists(select id from functional.alltypesagg) end
ERROR: IllegalStateException: Failed analysis after expr substitution.
CAUSED BY: ClassCastException: org.apache.impala.analysis.SlotRef cannot be cast to org.apache.impala.analysis.Subquery

These predicates are not expected to be supported - since we don't support arbitrary subqueries in where - see IMPALA-5226 - but we should produce a more meaningful error, like

[localhost.EXAMPLE.COM:21000] default> explain select * from functional.alltypes t
where cast((t.id IN (select id from functional.alltypesagg) or t.bool_col = false) as string) is not
 null;
Query: explain select * from functional.alltypes t
where cast((t.id IN (select id from functional.alltypesagg) or t.bool_col = false) as string) is not
 null
ERROR: AnalysisException: Unsupported IS NULL predicate that contains a subquery: CAST((t.id IN (SEL
ECT id FROM functional.alltypesagg) OR t.bool_col = FALSE) AS STRING) IS NOT NULL