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https://issues.apache.org/jira/browse/HIVE-8895?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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cw updated HIVE-8895:
---------------------
Attachment: HIVE-8895.2.patch
Add test case.
> 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: 0.13.0, 0.14.0, 0.13.1
> Reporter: cw
> Priority: Minor
> Labels: patch
> Attachments: HIVE-8895.1.patch, HIVE-8895.2.patch
>
>
> 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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