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From "Phabricator (JIRA)" <>
Subject [jira] [Commented] (HIVE-3509) Exclusive locks are not acquired when using dynamic partitions
Date Fri, 19 Apr 2013 11:39:16 GMT


Phabricator commented on HIVE-3509:

njain has commented on the revision "HIVE-3509 [jira] Exclusive locks are not acquired when
using dynamic partitions".

  ql/src/java/org/apache/hadoop/hive/ql/lockmgr/ This is a incompatible
change, and may break many existing apps.

  For eg: in FB we log the query along with inputs and outputs, and this will leave the
  burden on the client to change / to @ appropriately.

  Although it is not ideal, but let us stick with the format:

  db@table@partns. where partitions is of partitionCol1/partitionCol2


To: JIRA, MattMartin
Cc: njain

> Exclusive locks are not acquired when using dynamic partitions
> --------------------------------------------------------------
>                 Key: HIVE-3509
>                 URL:
>             Project: Hive
>          Issue Type: Bug
>          Components: Locking
>    Affects Versions: 0.9.0
>            Reporter: Matt Martin
>            Assignee: Matt Martin
>         Attachments: HIVE-3509.1.patch.txt, HIVE-3509.D10065.1.patch, HIVE-3509.D10065.2.patch,
HIVE-3509.D10065.3.patch, HIVE-3509.D10065.4.patch
> 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|]
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|], the observed behavior
is no longer consistent with the behavior described above.  [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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