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From "Jason Dere (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-7090) Support session-level temporary tables in Hive
Date Wed, 02 Jul 2014 20:10:25 GMT

    [ https://issues.apache.org/jira/browse/HIVE-7090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14050646#comment-14050646
] 

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

Are you referring to the ACID work that was done with HIVE-5317? My impression was that it
would not be applicable for temp tables, because the temp table is only visible to the current
session.  2 different sessions writing to a temp table with the same name will be updating
their own separate version of the table, and will be unaffected by any updates from the other
session.

> 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: Jason Dere
>         Attachments: HIVE-7090.1.patch, HIVE-7090.2.patch, HIVE-7090.3.patch, HIVE-7090.4.patch,
HIVE-7090.5.patch, HIVE-7090.6.patch, HIVE-7090.7.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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