Paul Shearer created SPARK-14241:
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Summary: Output of monotonically_increasing_id lacks stable
relation with rows of DataFrame
Key: SPARK-14241
URL: https://issues.apache.org/jira/browse/SPARK-14241
Project: Spark
Issue Type: Bug
Components: PySpark, Spark Core
Affects Versions: 1.6.1, 1.6.0
Reporter: Paul Shearer
If you use monotonically_increasing_id() to append a column of IDs to a
DataFrame, the IDs do not have a stable, deterministic relationship to the rows
they are appended to. A given ID value can land on different rows depending on
what happens in the task graph:
http://stackoverflow.com/questions/35705038/how-do-i-add-an-persistent-column-of-row-ids-to-spark-dataframe/35706321#35706321
>From a user perspective this behavior is very unexpected, and many things one
>would like to do with an ID column are only possible under very narrow
>circumstances. The function should either be made deterministic, or there
>should be a prominent warning note in the API docs regarding its behavior.
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