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Posted to issues@kylin.apache.org by "Dayue Gao (JIRA)" <ji...@apache.org> on 2017/01/13 11:17:26 UTC

[jira] [Created] (KYLIN-2386) Revert KYLIN-2349 and KYLIN-2353

Dayue Gao created KYLIN-2386:
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             Summary: Revert KYLIN-2349 and KYLIN-2353
                 Key: KYLIN-2386
                 URL: https://issues.apache.org/jira/browse/KYLIN-2386
             Project: Kylin
          Issue Type: Task
          Components: Metadata
    Affects Versions: v2.0.0
            Reporter: Dayue Gao
            Assignee: Dayue Gao


In KYLIN-2349 and KYLIN-2353, we optimized performance of BitmapCounter by changing its storage format. Cardinality and serialized size are recorded in the header of the new format, enables us to retrieve those information without deserialize the data.

In fact, cardinality and serialized size can be quickly calculated just from the header of [roaring format|https://github.com/RoaringBitmap/RoaringFormatSpec/]. Performance tests show that we could achieve the same performance boost without the format change of BitmapCounter. The benefits are
* no need to rebuild existing cube to get better performance
* no need to maintain two formats and deal with compatibility issues



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