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From "hyoungjunkim (JIRA)" <j...@apache.org>
Subject [jira] [Created] (TAJO-178) Implements StorageManager for Vectorized Engine
Date Wed, 11 Sep 2013 11:05:51 GMT
hyoungjunkim created TAJO-178:
---------------------------------

             Summary: Implements StorageManager for Vectorized Engine
                 Key: TAJO-178
                 URL: https://issues.apache.org/jira/browse/TAJO-178
             Project: Tajo
          Issue Type: Improvement
          Components: storage
    Affects Versions: 0.2-incubating
            Reporter: hyoungjunkim
         Attachments: tajo_storage_manager.png

The current StorageManager does not provide scan scheduling function. All scan operations
run concurrently. This is the cause of random disk access and disk read performance is not
good.
The proposed StorageManager is based on double buffering. Each disk has a scheduler to schedule
by order of scanned adjust. Each Scanner has a InputStream and a Tuple pool. The next() operation
of ScanNode is blocked until Tuple pool is filled. Assigned Scanner by the scheduler read
data(xMB) and fills Tuple Pool and notifies to next() operation. After scanning Scanner re-enter
DiskScanQueue.
In this way Scanner can pass column vector to Vectorized Query Engine.
See the attached file.


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