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From "Matt Martin (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-3509) Exclusive locks are not acquired when using dynamic partitions
Date Thu, 27 Sep 2012 17:12:07 GMT

     [ https://issues.apache.org/jira/browse/HIVE-3509?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Matt Martin updated HIVE-3509:
------------------------------

    Attachment: HIVE-3509.1.patch.txt

I'm attaching my first pass attempt at a solution.  I ran some manual tests to confirm that
things seemed to be working as expected after applying the patch. As far as automated tests
are concerned, I thought it might be useful to add the list of locks to the prehook output,
but I have not looked into doing that yet.
                
> Exclusive locks are not acquired when using dynamic partitions
> --------------------------------------------------------------
>
>                 Key: HIVE-3509
>                 URL: https://issues.apache.org/jira/browse/HIVE-3509
>             Project: Hive
>          Issue Type: Bug
>          Components: Locking
>    Affects Versions: 0.9.0
>            Reporter: Matt Martin
>         Attachments: HIVE-3509.1.patch.txt
>
>
> If locking is enabled, the acquireReadWriteLocks() method in org.apache.hadoop.hive.ql.Driver
iterates through all of the input and output entities of the query plan and attempts to acquire
the appropriate locks.  In general, it should acquire SHARED locks for all of the input entities
and exclusive locks for all of the output entities (see the Hive wiki page on [locking|https://cwiki.apache.org/confluence/display/Hive/Locking]
for more detailed information).
> When the query involves dynamic partitions, the situation is a little more subtle.  As
the Hive wiki notes (see previous link):
> {quote}
> in some cases, the list of objects may not be known - for eg. in case of dynamic partitions,
the list of partitions being modified is not known at compile time - so, the list is generated
conservatively. Since the number of partitions may not be known, an exclusive lock is taken
on the table, or the prefix that is known.
> {quote}
> After [HIVE-1781|https://issues.apache.org/jira/browse/HIVE-1781], the observed behavior
is no longer consistent with the behavior described above.  [HIVE-1781|https://issues.apache.org/jira/browse/HIVE-1781]
appears to have altered the logic so that SHARED locks are acquired instead of EXCLUSIVE locks
whenever the query involves dynamic partitions.

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