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From "Alicia Ying Shu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-1580) Support UNION ALL
Date Tue, 17 Mar 2015 23:08:39 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-1580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14366274#comment-14366274
] 

Alicia Ying Shu commented on PHOENIX-1580:
------------------------------------------

UNION ALL is mostly used when you would like to access different tables, thus likely different
CFs. SubSelects in UNION ALL are executed in parallel and in streaming fashion. Caching a
large amount of CF data for multiple subselects may not be feasible and can be expensive too.
If CF data is small, scan them should be fast. 

> Support UNION ALL
> -----------------
>
>                 Key: PHOENIX-1580
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-1580
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: Alicia Ying Shu
>            Assignee: Alicia Ying Shu
>         Attachments: phoenix-1580.patch, unionall-wipe.patch
>
>
> Select * from T1
> UNION ALL
> Select * from T2



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