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https://issues.apache.org/jira/browse/HIVE-12411?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15024085#comment-15024085
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Pengcheng Xiong commented on HIVE-12411:
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The test cases failures are unrelated besides metadataonly1.q and
optimize_nullscan.q. Analyze the golden file difference for both of them and
update them accordingly. Pushed to master. Thanks [~ashutoshc] for the review!
> Remove counter based stats collection mechanism
> -----------------------------------------------
>
> Key: HIVE-12411
> URL: https://issues.apache.org/jira/browse/HIVE-12411
> Project: Hive
> Issue Type: Task
> Components: Statistics
> Reporter: Pengcheng Xiong
> Assignee: Pengcheng Xiong
> Attachments: HIVE-12411.01.patch, HIVE-12411.02.patch
>
>
> Following HIVE-12005, HIVE-12164, we have removed jdbc and hbase stats
> collection mechanism. Now we are targeting counter based stats collection
> mechanism. The main advantages are as follows (1) counter based stats has
> limitation on the length of the counter itself, if it is too long, MD5 will
> be applied. (2) when there are a large number of partitions and columns, we
> need to create a large number of counters in memory. This will put a heavy
> load on the M/R AM or Tez AM etc. FS based stats will do a better job.
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