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Posted to issues@tajo.apache.org by "Jinho Kim (JIRA)" <ji...@apache.org> on 2015/11/10 10:01:11 UTC
[jira] [Updated] (TAJO-1271) Improve memory usage of Hash-shuffle
[ https://issues.apache.org/jira/browse/TAJO-1271?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jinho Kim updated TAJO-1271:
----------------------------
Summary: Improve memory usage of Hash-shuffle (was: Improve memory usage in HashShuffleFileWriteExec)
> Improve memory usage of Hash-shuffle
> ------------------------------------
>
> Key: TAJO-1271
> URL: https://issues.apache.org/jira/browse/TAJO-1271
> Project: Tajo
> Issue Type: Improvement
> Components: Data Shuffle
> Affects Versions: 0.9.0
> Reporter: Jinho Kim
> Assignee: Jinho Kim
>
> Currently, Hash-shuffle keeps intermediate file appender and tuple list in memory and the required memory will be in proportion to the input size
> If input size is 10GB, the hash-join key partition count will be 78125 (10TB / 128MB) and the required memory is 10GB (78125 * 128KB).
> We should improve the hash-shuffle file writer as following :
> * Separate the buffer from the file writer
> * Keep the tuples in off-heap buffer and reuse the buffer
> * Flush the buffers, if total buffer capacity is required more than maxBufferSize
> * Write the partition files asynchronously
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