[jira] [Commented] (KYLIN-2457) Should copy the latest dictionaries on dimension tables in a batch merge job

["Dayue Gao (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KYLIN-2457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15878043#comment-15878043 ] 

Dayue Gao commented on KYLIN-2457:
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+1. Hi [~zhengd], it would be better if you update the comments of {{makeDictForNewSegment}} and {{makeSnapshotForNewSegment}}?

> Should copy the latest dictionaries on dimension tables in a batch merge job
> ----------------------------------------------------------------------------
>
>                 Key: KYLIN-2457
>                 URL: https://issues.apache.org/jira/browse/KYLIN-2457
>             Project: Kylin
>          Issue Type: Bug
>            Reporter: zhengdong
>            Priority: Critical
>         Attachments: KYLIN-2457-Should-copy-the-latest-dictionaries-on-di.patch
>
>
> In a batch merge job, we need to create dictionaries for all dimensions for the new segment. For those dictionaries on dimension table, we currently just copy them from the earliest segment of the merging segments. 
> However, we should select the newest dictionary for the new segment, since the incremental dimension table is allowed. The older dictionary can't find the records corresponding to the new key added to a dimension table and  lead wrong query result.



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