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Posted to issues@hive.apache.org by "Pablo Junge (Jira)" <ji...@apache.org> on 2019/12/05 22:27:00 UTC
[jira] [Commented] (HIVE-21174) hive.stats.ndv.error parameter
documentation issue
[ https://issues.apache.org/jira/browse/HIVE-21174?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16989213#comment-16989213 ]
Pablo Junge commented on HIVE-21174:
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Wiki updated from
Current documentation shows:
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Standard error allowed for NDV estimates, expressed in percentage. This provides a tradeoff between accuracy and compute cost. A lower value for the error indicates higher accuracy and a higher compute cost. (NDV means number of distinct values.)
To
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The standard error allowed for NDV estimates, expressed in percentage. This provides a tradeoff between accuracy and compute cost. A lower value for the error indicates higher accuracy and a higher compute cost. (NDV means the number of distinct values.). It only affects the FM-Sketch (not the HLL algorithm which is the default), where it computes the number of necessary bitvectors to achieve the accuracy.
> hive.stats.ndv.error parameter documentation issue
> --------------------------------------------------
>
> Key: HIVE-21174
> URL: https://issues.apache.org/jira/browse/HIVE-21174
> Project: Hive
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 2.0.0, 2.0.1, 2.0.2, 2.1.0, 2.1.1, 2.1.2, 2.2.0, 2.3.0, 3.0.0, 2.4.0, 2.2.1, 2.3.1, 2.3.2, 2.3.3, 3.1.0, 3.0.1, 3.10, 3.2.0, 3.1.1, 2.3.4, 3.1.2
> Reporter: Pablo Junge
> Assignee: Pablo Junge
> Priority: Major
> Fix For: 2.0.0, 2.0.1, 2.0.2, 2.1.0, 2.1.1, 2.1.2, 2.2.0, 2.3.0, 3.0.0, 2.4.0, 2.2.1, 2.3.1, 2.3.2, 2.3.3, 3.1.0, 3.0.1, 3.10, 3.2.0, 3.1.1, 2.3.4
>
>
> Hive documentation for hive.stats.ndv.error does not specify that hive.stats.ndv.error will only affect FM Sketch and not HLL.
>
> https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties
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