[ https://issues.apache.org/jira/browse/SPARK-22164?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zhenhua Wang closed SPARK-22164. -------------------------------- > support histogram in estimating the cardinality of aggregate (or group-by) > operator > ----------------------------------------------------------------------------------- > > Key: SPARK-22164 > URL: https://issues.apache.org/jira/browse/SPARK-22164 > Project: Spark > Issue Type: Sub-task > Components: SQL > Affects Versions: 2.2.0 > Reporter: Ron Hu > > Histogram is effective in dealing with skewed distribution. After we generate > histogram information for column statistics, we need to adjust aggregate (or > group-by) cardinality estimation based on equi-height histogram information. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org