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Posted to dev@kylin.apache.org by "Shaofeng SHI (JIRA)" <ji...@apache.org> on 2016/01/04 04:21:40 UTC
[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
Shaofeng SHI created KYLIN-1278:
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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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