Matt Martin created HIVE-3509:
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Summary: 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
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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