You are viewing a plain text version of this content. The canonical link for it is here.

Posted to issues@hive.apache.org by "Gopal V (JIRA)" <ji...@apache.org> on 2017/12/03 06:22:00 UTC

[jira] [Updated] (HIVE-18079) Statistics: Allow HyperLogLog to be merged to the lowest-common-denominator bit-size

     [ https://issues.apache.org/jira/browse/HIVE-18079?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gopal V updated HIVE-18079:
---------------------------
    Attachment: HIVE-18079.1.patch

> Statistics: Allow HyperLogLog to be merged to the lowest-common-denominator bit-size
> ------------------------------------------------------------------------------------
>
>                 Key: HIVE-18079
>                 URL: https://issues.apache.org/jira/browse/HIVE-18079
>             Project: Hive
>          Issue Type: Improvement
>          Components: Standalone Metastore, Statistics
>    Affects Versions: 3.0.0
>            Reporter: Gopal V
>            Assignee: Gopal V
>         Attachments: HIVE-18079.1.patch
>
>
> HyperLogLog can merge a 14 bit HLL into a 10 bit HLL bitset, because of its mathematical hash distribution & construction.
> Allow the squashing of a 14 bit HLL -> 10 bit HLL without needing a second scan over the data-set.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)