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https://issues.apache.org/jira/browse/HIVE-15723?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Remus Rusanu updated HIVE-15723:
--------------------------------
    Attachment: HIVE-15723.02.patch

02.patch adds a conf setting hive.cbo.show.warnings (default false) to control 
the logging of misisng columns and a test case. Missing stats warnings looks 
like this:

{noformat}
No Stats for default@missing_stats_t1, Columns: value
No Stats for default@missing_stats_t2, Columns: key
No Stats for default@missing_stats_t3, Columns: value
{noformat}

Which is exactly the same output as the missing stats logged (to hive.log) in 
RelOpHiveTable.updateColStats, as is actually the very same logMsg.

> Hive should report a warning about missing table/column statistics to user.
> ---------------------------------------------------------------------------
>
>                 Key: HIVE-15723
>                 URL: https://issues.apache.org/jira/browse/HIVE-15723
>             Project: Hive
>          Issue Type: Bug
>          Components: Query Processor
>            Reporter: Remus Rusanu
>            Assignee: Remus Rusanu
>            Priority: Minor
>             Fix For: 2.2.0
>
>         Attachments: HIVE-15723.01.patch, HIVE-15723.02.patch
>
>
> Many Hive performance issues are due to missing statistics. Either all, table 
> or column statistics are missing. Potentially a new partition has been added 
> and customer forgot to gather stats for that partition.
> A simple warning about a table or column missing statistics can be very 
> helpful and makes hive more user friendly. Hive already has this information, 
> its a matter of printing it out.



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