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https://issues.apache.org/jira/browse/HIVE-18200?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Deepak Jaiswal resolved HIVE-18200.
-----------------------------------
Resolution: Duplicate
Duplicate if HIVE-17851
> Bucket Map Join : Use correct algorithm to pick the big table
> -------------------------------------------------------------
>
> Key: HIVE-18200
> URL: https://issues.apache.org/jira/browse/HIVE-18200
> Project: Hive
> Issue Type: Bug
> Reporter: Deepak Jaiswal
> Assignee: Deepak Jaiswal
>
> Currently the algorithm to pick the big table is flawed due to complexity
> associated with n-way joins.
> It could result in OOM, consider the following scenario,
> CREATE TABLE tab_part (key int, value string) PARTITIONED BY(ds STRING)
> CLUSTERED BY (key) INTO 4 BUCKETS STORED AS TEXTFILE;
> CREATE TABLE tab(key int, value string) PARTITIONED BY(ds STRING) CLUSTERED
> BY (key) INTO 2 BUCKETS STORED AS TEXTFILE;
> Lets say tab has size of 2GB and tab_part has size of 500MB and
> noconditionaltasksize is 200MB, then bucket map join should not happen as
> atleast one hash table will be more than 250 MB, which may cause OOM.
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