[jira] [Updated] (HIVE-7832) Do ORC dictionary check at a finer level and preserve encoding across stripes

["Prasanth J (JIRA)" <ji...@apache.org>]

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

Prasanth J updated HIVE-7832:
-----------------------------
    Attachment: HIVE-7832.9.patch

Addressed Gopal's review comments.

> 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, HIVE-7832.3.patch, HIVE-7832.4.patch, HIVE-7832.5.patch, HIVE-7832.6.patch, HIVE-7832.7.patch, HIVE-7832.8.patch, HIVE-7832.9.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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