[jira] [Commented] (HIVE-3652) Join optimization for star schema

["Vikram Dixit K (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-3652?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13542361#comment-13542361 ] 

Vikram Dixit K commented on HIVE-3652:
--------------------------------------

[~amareshwari] I am quite interested in this jira and was wondering what phase you are in with respect to design/implementation. I would like to collaborate with you on this if possible. Please let me know.

Thanks
Vikram.
                
> Join optimization for star schema
> ---------------------------------
>
>                 Key: HIVE-3652
>                 URL: https://issues.apache.org/jira/browse/HIVE-3652
>             Project: Hive
>          Issue Type: Improvement
>          Components: Query Processor
>            Reporter: Amareshwari Sriramadasu
>            Assignee: Amareshwari Sriramadasu
>
> Currently, if we join one fact table with multiple dimension tables, it results in multiple mapreduce jobs for each join with dimension table, because join would be on different keys for each dimension. 
> Usually all the dimension tables will be small and can fit into memory and so map-side join can used to join with fact table.
> In this issue I want to look at optimizing such query to generate single mapreduce job sothat mapper loads dimension tables into memory and joins with fact table on different keys as well.

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