Owen O'Malley created HIVE-13232:
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Summary: Aggressively drop compression buffers in ORC OutStreams
Key: HIVE-13232
URL: https://issues.apache.org/jira/browse/HIVE-13232
Project: Hive
Issue Type: Bug
Components: ORC
Reporter: Owen O'Malley
Assignee: Owen O'Malley
In Hive 0.11, when ORC's OutStream's were flushed they dropped all of the their
buffers. In the patch for HIVE-4342, we inadvertently changed that behavior so
that one of the buffers is held on to. For queries with a lot of writers and
thus under significant memory pressure this can have a significant impact on
the memory usage.
Note that "hive.optimize.sort.dynamic.partition" avoids this problem by sorting
on the dynamic partition key and thus only a single ORC writer is open at once.
This will use memory more effectively and avoid creating ORC files with very
small stripes, which will produce better downstream performance.
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