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https://issues.apache.org/jira/browse/HIVE-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13427069#comment-13427069
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Lianhui Wang commented on HIVE-3306:
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also i think there have another context.
example:ON (a.key = b.key and a.key=10)
this should scan the 10 bucket's file.not all bucket's file in the table's path.
> SMBJoin/BucketMapJoin should be allowed only when join key expression is
> exactly matches with sort/cluster key
> --------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-3306
> URL: https://issues.apache.org/jira/browse/HIVE-3306
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Affects Versions: 0.10.0
> Reporter: Navis
> Assignee: Navis
> Priority: Minor
>
> CREATE TABLE bucket_small (key int, value string) CLUSTERED BY (key) SORTED
> BY (key) INTO 2 BUCKETS STORED AS TEXTFILE;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket1outof4.txt' INTO TABLE
> bucket_small;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket2outof4.txt' INTO TABLE
> bucket_small;
> CREATE TABLE bucket_big (key int, value string) CLUSTERED BY (key) SORTED BY
> (key) INTO 4 BUCKETS STORED AS TEXTFILE;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket1outof4.txt' INTO TABLE
> bucket_big;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket2outof4.txt' INTO TABLE
> bucket_big;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket3outof4.txt' INTO TABLE
> bucket_big;
> load data local inpath
> '/home/navis/apache/oss-hive/data/files/srcsortbucket4outof4.txt' INTO TABLE
> bucket_big;
> select count(*) FROM bucket_small a JOIN bucket_big b ON a.key + a.key =
> b.key;
> select /* + MAPJOIN(a) */ count(*) FROM bucket_small a JOIN bucket_big b ON
> a.key + a.key = b.key;
> returns 116 (same)
> But with BucketMapJoin or SMBJoin, it returns 61. But this should not be
> allowed cause hash(a.key) != hash(a.key + a.key).
> Bucket context should be utilized only with exact matching join expression
> with sort/cluster key.
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