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https://issues.apache.org/jira/browse/PIG-4819?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Koji Noguchi updated PIG-4819:
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Attachment: pig-4819-v01.patch
Attaching a patch that
* Use jobid and taskid as the seed.
* A test case to make sure attempts from the same task would produce a same
random sequence
* (Unrelated, but) fixing a minor bug in testUniqueID where results weren't
checked properly.
I only changed {{./src/org/apache/pig/builtin/RANDOM.java}} but not
{{./contrib/piggybank/java/src/main/java/org/apache/pig/piggybank/evaluation/math/RANDOM.java}}.
Let me know if I should make the same change.
> RANDOM() udf can lead to missing or redundant records
> -----------------------------------------------------
>
> Key: PIG-4819
> URL: https://issues.apache.org/jira/browse/PIG-4819
> Project: Pig
> Issue Type: Bug
> Reporter: Koji Noguchi
> Assignee: Koji Noguchi
> Attachments: pig-4819-v01.patch
>
>
> When RANDOM() value is used for grouping/distinct/etc, it breaks the
> mapreduce rule and can lead to redundant or missing records.
> Some discussion can be found in
> https://issues.apache.org/jira/browse/PIG-3257?focusedCommentId=13669195#comment-13669195
> We should make RANDOM less random so that it'll produce the same sequence of
> random values from the task retries.
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