Fang-Yu Rao created IMPALA-13262:
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Summary: Predicate pushdown causes incorrect results in join
condition
Key: IMPALA-13262
URL: https://issues.apache.org/jira/browse/IMPALA-13262
Project: IMPALA
Issue Type: Bug
Reporter: Fang-Yu Rao
Assignee: Fang-Yu Rao
We found that in some scenario Apache Impala could incorrectly push predicates
to scan nodes, which in turn produces the wrong result. The following is a
concrete example to reproduce the issue.
{code:java}
create table department ( dept_no integer, dept_rank integer, start_date
timestamp,end_date timestamp);
insert into department values(1,1,'2024-01-01','2024-01-02');
insert into department values(1,2,'2024-01-02','2024-01-03');
insert into department values(1,3,'2024-01-03','2024-01-03');
create table employee (employee_no integer, depart_no integer);
insert into employee values (1,1);
// The following should return 0 row. However Apache Impala produces one row.
select * from employee t1
inner join (
select * from
(
select dept_no,dept_rank,start_date,end_date
,row_number() over(partition by dept_no order by dept_rank) rn
from department
) t2
where rn=1
) t2
on t1.depart_no=t2.dept_no
where t2.start_date=t2.end_date
{code}
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