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https://issues.apache.org/jira/browse/TAJO-178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13766233#comment-13766233
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Hudson commented on TAJO-178:
-----------------------------
SUCCESS: Integrated in Tajo-trunk-postcommit #431 (See
[https://builds.apache.org/job/Tajo-trunk-postcommit/431/])
TAJO-178: Implements StorageManager for scanning asynchronously. (only fixed
CHANGES.txt) (hyunsik:
https://git-wip-us.apache.org/repos/asf?p=incubator-tajo.git&a=commit&h=f664e0ccfc59d31b3fab816f935730da53a484bf)
* CHANGES.txt
> Implements StorageManager for scanning asynchronously
> -----------------------------------------------------
>
> 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
> Assignee: hyoungjunkim
> Fix For: 0.2-incubating
>
> Attachments: TAJO-178_1.path, TAJO-178_3.patch, TAJO-178_4.patch,
> TAJO-178.patch_2, TAJO-178.path, 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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