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https://issues.apache.org/jira/browse/PIG-3649?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Travis Woodruff updated PIG-3649:
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Attachment: PIG-3469.patch
Attaching path that updates {{aggregate()}} to count number of result tuples.
Includes two new tests:
- One that shows that basic aggregation of multiple columns works
- Another that reproduces the issue reported here. This requires aggregating >
10,000 rows, so it is a bit slow. Suggestions for alternative approaches
welcome.
> POPartialAgg incorrectly calculates size reduction when multiple values
> aggregated
> ----------------------------------------------------------------------------------
>
> Key: PIG-3649
> URL: https://issues.apache.org/jira/browse/PIG-3649
> Project: Pig
> Issue Type: Bug
> Affects Versions: 0.11, 0.12.0, 0.11.1
> Reporter: Travis Woodruff
> Attachments: PIG-3469.patch
>
>
> {{POPartialAgg.aggregate()}} counts the number of output columns
> ({{valueTuple.size() - 1}}), but {{checkSizeReduction()}} compares this to
> the number of input tuples.
> When multiple columns are aggregated, this causes the reduction factor to be
> calculated as too high by a factor of the number of columns being aggregated,
> which causes in-memory aggregation to be disabled when it should not be,
> adversely affecting performance,
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