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https://issues.apache.org/jira/browse/KYLIN-5309?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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pengfei.zhan updated KYLIN-5309:
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Description:
At present, the kylin5 already provides a runtime join scenario:
non-pre-computation which can be defined when creating a model. Usually,
non-pre-computation is used for the scenario of many-to-many to avoid data
blowing up dramatically when building the flat table.
This issue will propose one more flexible runtime join scenario for kylin5.
This feature is the excluded table. More information will be introduced by the
Chinese document in the following comments.
was:
This issue will propose the behavior of the excluded table, it makes the
feature more flexible. Previously, excluded columns were subject to their
corresponding table, which meant we either excluded all columns or none of
them. However, we can rule out some of them of a table without participating in
pre-computation from now on.
1. This issue separates the non-pre-computation of lookup tables from this
feature. Usually, non-pre-computation is used for the scenario of many-to-many
to avoid data blowing up dramatically when building the flat table.
2. If the statement query the excluded column and index with foreign key is
preferred, snapshot join index to get the newest data.
3. Reloading table keeps the unaffected columns. Two important cases are as
follows: 1) Add a column to the excluded table, and the added column will be
treated as an excluded column automatically; 2) If the last un-excluded column
is removed, this table will be treated as an excluded table.
5. By design limitation, the excluded column should not participate in any
parameters of measure.
6. By design limitation, the excluded column in the snow model should not be
used as the foreign key.
> Propose more flexible runtime join scenarios for Kylin
> ------------------------------------------------------
>
> Key: KYLIN-5309
> URL: https://issues.apache.org/jira/browse/KYLIN-5309
> Project: Kylin
> Issue Type: New Feature
> Components: Metadata, Query Engine
> Affects Versions: 5.0-alpha
> Reporter: pengfei.zhan
> Assignee: pengfei.zhan
> Priority: Major
> Fix For: 5.0-alpha
>
>
> At present, the kylin5 already provides a runtime join scenario:
> non-pre-computation which can be defined when creating a model. Usually,
> non-pre-computation is used for the scenario of many-to-many to avoid data
> blowing up dramatically when building the flat table.
> This issue will propose one more flexible runtime join scenario for kylin5.
> This feature is the excluded table. More information will be introduced by
> the Chinese document in the following comments.
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