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https://issues.apache.org/jira/browse/DRILL-3429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15062498#comment-15062498
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Victoria Markman commented on DRILL-3429:
-----------------------------------------

Verified fixed in 1.4.0

{code}
#Tue Dec 15 23:00:30 UTC 2015
git.commit.id.abbrev=2fbe668
git.commit.user.email=par...@apache.org
git.commit.message.full=DRILL-4152\: Add trace logging to  Parquet reader for 
performance tuning.\n
git.commit.id=2fbe668e8dcb3d06f345feb32a3d2ab1559f3645
{code}

Tests added in: Functional/window_functions/statistical_aggregates

> DrillAvgVarianceConvertlet may produce wrong results while rewriting stddev, 
> variance
> -------------------------------------------------------------------------------------
>
>                 Key: DRILL-3429
>                 URL: https://issues.apache.org/jira/browse/DRILL-3429
>             Project: Apache Drill
>          Issue Type: Bug
>            Reporter: Mehant Baid
>            Assignee: Mehant Baid
>            Priority: Critical
>             Fix For: 1.3.0
>
>         Attachments: DRILL-3429.patch
>
>
> DrillAvgVarianceConvertlet currently rewrites aggregate functions like avg, 
> stddev, variance to simple computations. 
> Eg: 
> Stddev( x ) => power(
>          (sum(x * x) - sum( x ) * sum( x ) / count( x ))
>          / count( x ),
>          .5)
> Consider the case when the input is an integer. Now the rewrite contains 
> multiplication and division, which will bind to functions that operate on 
> integers however the expected result should be a double and since double has 
> more precision than integer we should be operating on double during the 
> multiplication and division.  



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