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https://issues.apache.org/jira/browse/HIVE-3421?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Feng Lu updated HIVE-3421:
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Description:
Compute (estimate) top k values for each column, and put the most skewed column
into skewed info, if user hasn't specified skew.
This feature depends on ListBucketing (create table skewed on)
https://cwiki.apache.org/Hive/listbucketing.html.
All column topk can be added to skewed info, if in the future skewed info
supports multiple independent columns.
The TopK algorithm is based on this paper:
http://www.cs.ucsb.edu/research/tech_reports/reports/2005-23.pdf
was:
Compute (estimate) top k values for each column, and put the most skewed column
into skewed info, if user hasn't specified skew.
This feature depends on ListBucketing (create skewed table)
https://cwiki.apache.org/Hive/listbucketing.html.
All column topk can be added to skewed info, if in the future skewed info
supports multiple independent columns.
The TopK algorithm is based on this paper:
http://www.cs.ucsb.edu/research/tech_reports/reports/2005-23.pdf
> Column Level Top K Values Statistics
> ------------------------------------
>
> Key: HIVE-3421
> URL: https://issues.apache.org/jira/browse/HIVE-3421
> Project: Hive
> Issue Type: New Feature
> Reporter: Feng Lu
> Assignee: Feng Lu
>
> Compute (estimate) top k values for each column, and put the most skewed
> column into skewed info, if user hasn't specified skew.
> This feature depends on ListBucketing (create table skewed on)
> https://cwiki.apache.org/Hive/listbucketing.html.
> All column topk can be added to skewed info, if in the future skewed info
> supports multiple independent columns.
> The TopK algorithm is based on this paper:
> http://www.cs.ucsb.edu/research/tech_reports/reports/2005-23.pdf
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