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https://issues.apache.org/jira/browse/KYLIN-1345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15129873#comment-15129873
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hongbin ma commented on KYLIN-1345:
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the datatype comes from hive. suppose a hive column named "price" is of type
decimal(6,2) and in the fact table every record's price is guaranteed to be
less than 10000, then it's okay.
but in kylin cubes&query, we do aggregations, it means sum(price) may exceed
10000, however our measure type inherits the type from the hive column, which
is problematic.
please let me know if you still have concerns.
> measure type expansion when dealing sum of decimal metric
> ---------------------------------------------------------
>
> Key: KYLIN-1345
> URL: https://issues.apache.org/jira/browse/KYLIN-1345
> Project: Kylin
> Issue Type: Improvement
> Reporter: hongbin ma
> Assignee: Edward Zhang
> Labels: newbie
>
> suppose a metric column price is of type decimal (6,2), the sum aggregator of
> it might exceed the maximal of decimal (6,2). Currently for metric
> aggregators we inherite the column's type in hive. We should think auto
> expanding decimal type to decimal(18,4) (just an example) for such cases
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