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https://issues.apache.org/jira/browse/IMPALA-7814?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tim Armstrong resolved IMPALA-7814.
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Resolution: Incomplete
I read this a couple of times and I don't understand exactly what the problem
identified is. I dont' think we're likely to get to it soon so I'll just close.
> AggregationNode's memory estimate should be based on NDV only for
> non-grouping aggs
> ------------------------------------------------------------------------------------
>
> Key: IMPALA-7814
> URL: https://issues.apache.org/jira/browse/IMPALA-7814
> Project: IMPALA
> Issue Type: Sub-task
> Components: Frontend
> Reporter: Pooja Nilangekar
> Priority: Major
> Labels: resource-management
>
> Currently, the AggregationNode always computes the NDV to estimate the number
> of rows. However, for grouping aggregates, the entire input has to be
> consumed before the output can be produced, hence its memory estimate should
> not consider the NDV. This is acceptable for non-grouping aggregates because
> it only need to store the value expression during the build phase, instead of
> the entire tuple.
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