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https://issues.apache.org/jira/browse/KYLIN-1792?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wang Cheng updated KYLIN-1792:
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Attachment: 0001-KYLIN-1792-it-fixed-when-join-contains-subquery-kyli.patch
> behaviours for non-aggregated queries
> -------------------------------------
>
> Key: KYLIN-1792
> URL: https://issues.apache.org/jira/browse/KYLIN-1792
> Project: Kylin
> Issue Type: Improvement
> Affects Versions: v1.5.2
> Reporter: hongbin ma
> Assignee: Yiming Liu
> Attachments:
> 0001-KYLIN-1792-it-fixed-when-join-contains-subquery-kyli.patch,
> 0001-KYLIN-1792-it-fixed-when-join-contains-subquery-kyli.patch
>
>
> Even though kylin is not designed for non-aggregated queries, people do
> frequently use queries like
> {code:sql}
> select * from fact limit
> {code}
> to verify their cubes. Recently many new users reported problems when running
> such queries, we'll use this JIRA as an umbrella to track all related issues.
> for such queries on fact table:
> - select * from fact : should return results from base cuboid (thus not raw
> fact table data) and MIGHT crash query server or region server
> - select * from fact limit x : should return results from base cuboid (thus
> not raw fact table data) and SHOULD NOT crash query server or region server.
> Current there's a known issue KYLIN-1787 fails to push down the limit value
> - select a,b from fact: should return results from base cuboid (thus not raw
> fact table data) and MIGHT crash query server or region server (when a or b
> contains is a measure, the query only works when you defined a sum() measure )
> - select a,b from fact limit x: should return results from base cuboid (thus
> not raw fact table data) and SHOULD NOT crash query server or region server
> (when a or b contains is a measure, the query only works when you defined a
> sum() measure)
> such four kinds of queries on look up tables should return correct results
> from the lookup table snapshot directly, and even without the limit clause,
> they have a low possibility to crash query server or region server because
> lookup table tends to be small. However, it's still better to make sure limit
> is taking effect.
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