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Posted to issues@hive.apache.org by "Vineet Garg (JIRA)" <ji...@apache.org> on 2017/08/12 22:49:00 UTC

[jira] [Updated] (HIVE-17308) Improvement in join cardinality estimation

     [ https://issues.apache.org/jira/browse/HIVE-17308?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vineet Garg updated HIVE-17308:
-------------------------------
    Attachment: HIVE-17308.1.patch

> Improvement in join cardinality estimation
> ------------------------------------------
>
>                 Key: HIVE-17308
>                 URL: https://issues.apache.org/jira/browse/HIVE-17308
>             Project: Hive
>          Issue Type: Improvement
>          Components: Query Planning
>            Reporter: Vineet Garg
>            Assignee: Vineet Garg
>         Attachments: HIVE-17308.1.patch
>
>
> Currently during logical planning join cardinality is estimated assuming no correlation among join keys (This estimation is done using exponential backoff). Physical planning on the other hand consider correlation for multi keys and uses different estimation. We should consider correlation during logical planning as well.



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