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Posted to issues@spark.apache.org by "Ron Hu (JIRA)" <ji...@apache.org> on 2017/11/21 01:44:00 UTC
[jira] [Comment Edited] (SPARK-21322) support histogram in filter
cardinality estimation
[ https://issues.apache.org/jira/browse/SPARK-21322?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16258601#comment-16258601 ]
Ron Hu edited comment on SPARK-21322 at 11/21/17 1:43 AM:
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Pull request 19357 was created while there were several dependencies that had not been merged yet at that time. As a result, it has caused many conflicts. I decided to close pull request 19357 and start a clean one. Please review the new pull request 19783 instead. Thanks.
was (Author: ron8hu):
Pull request 19357 was created while there were several dependencies that had not been defined yet at that time. As a result, it has caused many conflicts. I decided to close pull request 19357 and start a clean one. Please review the new pull request 19783 instead. Thanks.
> support histogram in filter cardinality estimation
> --------------------------------------------------
>
> Key: SPARK-21322
> URL: https://issues.apache.org/jira/browse/SPARK-21322
> Project: Spark
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 2.3.0
> Reporter: Ron Hu
>
> Histogram is effective in dealing with skewed distribution. After we generate histogram information for column statistics, we need to adjust filter estimation based on histogram data structure.
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