[jira] [Assigned] (SPARK-9978) Window functions require partitionBy to work as expected

["Davies Liu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-9978?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Davies Liu reassigned SPARK-9978:
---------------------------------

    Assignee: Davies Liu

> Window functions require partitionBy to work as expected
> --------------------------------------------------------
>
>                 Key: SPARK-9978
>                 URL: https://issues.apache.org/jira/browse/SPARK-9978
>             Project: Spark
>          Issue Type: Bug
>          Components: PySpark
>    Affects Versions: 1.4.1
>            Reporter: Maciej Szymkiewicz
>            Assignee: Davies Liu
>
> I am trying to reproduce following SQL query:
> {code}
> df.registerTempTable("df")
> sqlContext.sql("SELECT x, row_number() OVER (ORDER BY x) as rn FROM df").show()
> +----+--+
> |   x|rn|
> +----+--+
> |0.25| 1|
> | 0.5| 2|
> |0.75| 3|
> +----+--+
> {code}
> using PySpark API. Unfortunately it doesn't work as expected:
> {code}
> from pyspark.sql.window import Window
> from pyspark.sql.functions import rowNumber
> df = sqlContext.createDataFrame([{"x": 0.25}, {"x": 0.5}, {"x": 0.75}])
> df.select(df["x"], rowNumber().over(Window.orderBy("x")).alias("rn")).show()
> +----+--+
> |   x|rn|
> +----+--+
> | 0.5| 1|
> |0.25| 1|
> |0.75| 1|
> +----+--+
> {code}
> As a workaround It is possible to call partitionBy without additional arguments:
> {code}
> df.select(
>     df["x"],
>     rowNumber().over(Window.partitionBy().orderBy("x")).alias("rn")
> ).show()
> +----+--+
> |   x|rn|
> +----+--+
> |0.25| 1|
> | 0.5| 2|
> |0.75| 3|
> +----+--+
> {code}
> but as far as I can tell it is not documented and is rather counterintuitive considering SQL syntax. Moreover this problem doesn't affect Scala API:
> {code}
> import org.apache.spark.sql.expressions.Window
> import org.apache.spark.sql.functions.rowNumber
> case class Record(x: Double)
> val df = sqlContext.createDataFrame(Record(0.25) :: Record(0.5) :: Record(0.75))
> df.select($"x", rowNumber().over(Window.orderBy($"x")).alias("rn")).show
> +----+--+
> |   x|rn|
> +----+--+
> |0.25| 1|
> | 0.5| 2|
> |0.75| 3|
> +----+--+
> {code}



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