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Date: Mon, 23 Jun 2014 22:12:24 +0000 (UTC)
From: "Jason Dere (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: <JIRA.12715307.1400537426386.32589.1403561544913@arcas>
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Subject: [jira] [Commented] (HIVE-7090) Support session-level temporary
 tables in Hive
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    [ https://issues.apache.org/jira/browse/HIVE-7090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14041399#comment-14041399 ] 

Jason Dere commented on HIVE-7090:
----------------------------------

Yes good point.  The patch actually does this - each session will have its own scratch directory for temp tables, using the session ID (a UUID).  Within the session's temp table scratch directory, each created temp table will get its own directory, also generated using UUID.

> Support session-level temporary tables in Hive
> ----------------------------------------------
>
>                 Key: HIVE-7090
>                 URL: https://issues.apache.org/jira/browse/HIVE-7090
>             Project: Hive
>          Issue Type: Bug
>          Components: SQL
>            Reporter: Gunther Hagleitner
>            Assignee: Harish Butani
>         Attachments: HIVE-7090.1.patch, HIVE-7090.2.patch
>
>
> It's common to see sql scripts that create some temporary table as an intermediate result, run some additional queries against it and then clean up at the end.
> We should support temporary tables properly, meaning automatically manage the life cycle and make sure the visibility is restricted to the creating connection/session. Without these it's common to see left over tables in meta-store or weird errors with clashing tmp table names.
> Proposed syntax:
> CREATE TEMPORARY TABLE ....
> CTAS, CTL, INSERT INTO, should all be supported as usual.
> Knowing that a user wants a temp table can enable us to further optimize access to it. E.g.: temp tables should be kept in memory where possible, compactions and merging table files aren't required, ...


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