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From "Shaofeng SHI (JIRA)" <j...@apache.org>
Subject [jira] [Created] (KYLIN-1278) Query engine optimization: skip the condition checking on partition column if a segment's time is totaly included in the query range
Date Mon, 04 Jan 2016 03:21:40 GMT
Shaofeng SHI created KYLIN-1278:
-----------------------------------

             Summary: Query engine optimization: skip the condition checking on partition
column if a segment's time is totaly included in the query range
                 Key: KYLIN-1278
                 URL: https://issues.apache.org/jira/browse/KYLIN-1278
             Project: Kylin
          Issue Type: Improvement
          Components: Query Engine
            Reporter: Shaofeng SHI
            Assignee: liyang
             Fix For: Backlog


See an example: a cube (which is partitioned by date column "CAL_DT") has three segments:

S1, S2, S3;

Now a query like "select .... from fact_table where CAL_DT > 'yyyy-mm-dd' group by dimA,
dimB..." comes, and the "CAL_DT" is only used for filtering, not in group by; 

By checking the startTime/endTime, Kylin found S2 and S3 need be scanned, and S3 is totally
match the condition "CAL_DT > yyyy-mm-dd". Then when scan S3, Kylin can ignore the condition
on "CAL_DT", selecting a smaller cuboid, this should gain better performance. 

 



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