hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
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 Tue, 26 Aug 2014 18:51:59 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-7832.5.patch

Earlier patch made some complications related to clearing the dictionary entries. Fixed it
in this patch.

> 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
>
>
> 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.



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message