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https://issues.apache.org/jira/browse/SPARK-16207?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Owen updated SPARK-16207:
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    Priority: Minor  (was: Major)

Generally, things like RDD and DataFrame don't guarantee any order at all, 
unless they are product of an ordering operation like sort. I don't think 
blogs/SO are relevant as much as Spark docs, and they do cover this in places. 
If you have a specific suggestion, make a PR, but if this is a question, then 
it should be closed.

> order guarantees for DataFrames
> -------------------------------
>
>                 Key: SPARK-16207
>                 URL: https://issues.apache.org/jira/browse/SPARK-16207
>             Project: Spark
>          Issue Type: Documentation
>          Components: Spark Core
>    Affects Versions: 1.6.1
>            Reporter: Max Moroz
>            Priority: Minor
>
> There's no clear explanation in the documentation about what guarantees are 
> available for the preservation of order in DataFrames. Different blogs, SO 
> answers, and posts on course websites suggest different things. It would be 
> good to provide clarity on this.
> Examples of questions on which I could not find clarification:
> 1) Does groupby() preserve order?
> 2) Does take() preserve order?
> 3) Is DataFrame guaranteed to have the same order of lines as the text file 
> it was read from? (Or as the json file, etc.)



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