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

["Amareshwari Sriramadasu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-3652?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Amareshwari Sriramadasu updated HIVE-3652:
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    Attachment: HIVE-3652-tests.patch

Attaching test with .q and .out files, which is launching two MR jobs for star join queries.
                
> 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: Vikram Dixit K
>             Fix For: 0.11.0
>
>         Attachments: HIVE-3652-tests.patch
>
>
> 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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