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Posted to dev@hive.apache.org by "cw (JIRA)" <ji...@apache.org> on 2014/11/17 08:34:34 UTC
[jira] [Created] (HIVE-8895) bugs in mergejoin
cw created HIVE-8895:
------------------------
Summary: bugs in mergejoin
Key: HIVE-8895
URL: https://issues.apache.org/jira/browse/HIVE-8895
Project: Hive
Issue Type: Bug
Components: Query Processor
Affects Versions: 0.13.1, 0.13.0, 0.14.0
Reporter: cw
Priority: Minor
I got a IndexOutOfBoundsException with a SQL in hive0.13.1. But it runs well on hive0.11. Here is the example sql which can trigger the exception.
{code}
create table test_join_1(a string, b string);
create table test_join_2(a string, b string);
-- got an IndexOutOfBoundsException error
explain
select * from
(
SELECT a a, b b
FROM test_join_1
)t1
join
(
SELECT a a, b b
FROM test_join_1
)t2
on t1.a = t2.a
and t1.a = t2.b
join
(
select a from test_join_2
)t3 on t1.a = t3.a;
{code}
And here is some stack information:
{code}
java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
at java.util.ArrayList.rangeCheck(ArrayList.java:604)
at java.util.ArrayList.get(ArrayList.java:382)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.mergeJoins(SemanticAnalyzer.java:7403)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.mergeJoinTree(SemanticAnalyzer.java:7616)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.genPlan(SemanticAnalyzer.java:8946)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:9220)
...
{code}
But sql as below runs well.
{code}
explain select * from
(
SELECT a a, b b
FROM test_join_1
)t1
join
(
SELECT a a, b b
FROM test_join_1
)t2
on t1.a = t2.a
and t2.a = t2.b
join
(
select a from test_join_2
)t3 on t1.a = t3.a;
{code}
I didn't quite understand the details of mergejoin. But I noticed the patch in HIVE-5556 edited SemanticAnalyzer.java with the change below:
{code}
- if ((targetCondn == null) || (nodeCondn.size() != targetCondn.size())) {
- return -1;
+ if ( targetCondn == null ) {
+ return new ObjectPair(-1, null);
+ }
{code}
Maybe it's a good idea to revert the logic of the 'if' statement as before.
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