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Posted to issues@kylin.apache.org by "Zhong Yanghong (JIRA)" <ji...@apache.org> on 2017/08/31 11:01:13 UTC
[jira] [Updated] (KYLIN-2826) Add basic support classes for cube
planner algorithms
[ https://issues.apache.org/jira/browse/KYLIN-2826?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zhong Yanghong updated KYLIN-2826:
----------------------------------
Description:
Cube planner aims at recommending cost-effective cuboids. Currently we only consider {color:#f79232}*scanned row count*{color} at {color:#f79232}*query phase*{color} for the cost. The related formula is as follows:
bq. cuboid cost = scanned row count on target cuboid * query probability
As we know the base cuboid is to be prebuilt absolutely. If only the base cuboid is prebuilt, for other cuboids, the target cuboid will be the base cuboid and the _(scanned row count)_ is supposed to be large. When another cuboid is selected to be prebuilt, for its descendant cuboids including itself, it will be their target cuboid and the _(scanned row count)_ is supposed to become smaller. Thus, this newly cuboid will bring some benefit. We employ BPUS (benefit per unit space) for cuboid selection. The related formula for the benefit of a cuboid is as follows:
bq. cuboid benefit = total reduced cuboid cost) / (cuboid row count)
Cuboid selection is based on one basic rule:
bq. {color:#f79232}*RULE: Cuboids with more benefit will be preferred.*{color}
> Add basic support classes for cube planner algorithms
> -----------------------------------------------------
>
> Key: KYLIN-2826
> URL: https://issues.apache.org/jira/browse/KYLIN-2826
> Project: Kylin
> Issue Type: Sub-task
> Reporter: Zhong Yanghong
> Assignee: Zhong Yanghong
>
> Cube planner aims at recommending cost-effective cuboids. Currently we only consider {color:#f79232}*scanned row count*{color} at {color:#f79232}*query phase*{color} for the cost. The related formula is as follows:
> bq. cuboid cost = scanned row count on target cuboid * query probability
> As we know the base cuboid is to be prebuilt absolutely. If only the base cuboid is prebuilt, for other cuboids, the target cuboid will be the base cuboid and the _(scanned row count)_ is supposed to be large. When another cuboid is selected to be prebuilt, for its descendant cuboids including itself, it will be their target cuboid and the _(scanned row count)_ is supposed to become smaller. Thus, this newly cuboid will bring some benefit. We employ BPUS (benefit per unit space) for cuboid selection. The related formula for the benefit of a cuboid is as follows:
> bq. cuboid benefit = total reduced cuboid cost) / (cuboid row count)
> Cuboid selection is based on one basic rule:
> bq. {color:#f79232}*RULE: Cuboids with more benefit will be preferred.*{color}
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