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From "Prasanth J (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-7832) Do ORC dictionary check at a finer level and preserve encoding across stripes
Date Fri, 22 Aug 2014 07:29:11 GMT

     [ https://issues.apache.org/jira/browse/HIVE-7832?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Prasanth J updated HIVE-7832:
-----------------------------

    Attachment: HIVE-7832.2.patch

Addressed Gopal's review comment.

> Do ORC dictionary check at a finer level and preserve encoding across stripes
> -----------------------------------------------------------------------------
>
>                 Key: HIVE-7832
>                 URL: https://issues.apache.org/jira/browse/HIVE-7832
>             Project: Hive
>          Issue Type: Improvement
>    Affects Versions: 0.14.0
>            Reporter: Prasanth J
>            Assignee: Prasanth J
>         Attachments: HIVE-7832.1.patch, HIVE-7832.2.patch
>
>
> Currently ORC dictionary check happens while writing the stripe. Just before writing
stripe if ratio of dictionary entries to total non-null rows is greater than threshold then
the dictionary is discarded. Also, the decision of using dictionary or not is preserved across
stripes. This sometimes leads to costly insertion cost of O(logn) for each stripes when there
are too many distinct keys.



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