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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/Locking" by NamitJain
Date Wed, 05 May 2010 04:47:40 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/Locking" page has been changed by NamitJain.
http://wiki.apache.org/hadoop/Hive/Locking?action=diff&rev1=10&rev2=11

--------------------------------------------------

  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.
  
+ Two new configurable parameters will be added to decide the number of retries for the lock
and the 
+ wait time between each retry. If the number of retries are really high, it can lead to a
live lock.
+ Look at ZooKeeper (http://hadoop.apache.org/zookeeper/docs/r3.1.2/recipes.html#sc_recipes_Locks)
to
+ see how read/write locks can be implemented using the zookeeper apis. Note that instead
of waiting,
+ the lock request will be denied. The existing locks will be released, and all of them will
be retried
+ after the retry interval.
+ 
+ The default hive behavior will not be changed, and concurrency will not be supported.
+ 

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