[
https://issues.apache.org/jira/browse/SPARK-5030?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Michael Armbrust resolved SPARK-5030.
-------------------------------------
Resolution: Duplicate
> Approximated cardinality with HyperLogLog UDAF
> ----------------------------------------------
>
> Key: SPARK-5030
> URL: https://issues.apache.org/jira/browse/SPARK-5030
> Project: Spark
> Issue Type: New Feature
> Components: SQL
> Reporter: XIAO Pin
> Priority: Minor
> Original Estimate: 672h
> Remaining Estimate: 672h
>
> HyperLogLog is a good way to improve performance of cardinality
> calculate(count distinct), especially in the case of skew data. Of course,
> there will be some loss of accuracy：
> select hllc(a) from test_tbl group by b
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
