[jira] [Resolved] (SPARK-22629) incorrect handling of calls to random in UDFs

["Hyukjin Kwon (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-22629?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Hyukjin Kwon resolved SPARK-22629.
----------------------------------
    Resolution: Incomplete

> incorrect handling of calls to random in UDFs
> ---------------------------------------------
>
>                 Key: SPARK-22629
>                 URL: https://issues.apache.org/jira/browse/SPARK-22629
>             Project: Spark
>          Issue Type: Bug
>          Components: PySpark
>    Affects Versions: 2.1.0
>            Reporter: Michael H
>            Priority: Major
>              Labels: bulk-closed
>
> {code:none}
> df_br = spark.createDataFrame([{'name': 'hello'}])
> # udf creates a random integer
> udf_random_col =  udf(lambda: int(100*random.random()), IntegerType())
> # add a column to our DF using that udf
> df_br = df_br.withColumn('RAND', udf_random_col())
> df_br.show()
> +-----+----+
> | name|RAND|
> +-----+----+
> |hello|  68|
> +-----+----+
> # udf that adds 10 to an input column value
> random.seed(1234)
> udf_add_ten =  udf(lambda rand: rand + 10, IntegerType())
> # unexpected result due to re-evaluation
> df_br.withColumn('RAND_PLUS_TEN', udf_add_ten('RAND')).show()
> +-----+----+-------------+
> | name|RAND|RAND_PLUS_TEN|
> +-----+----+-------------+
> |hello|  72|           87|
> +-----+----+-------------+
> # workaround: cache the resulst after using the random number generating udf
> df_br.withColumn('RAND', udf_random_col()).cache().withColumn('RAND_PLUS_TEN', udf_add_ten('RAND')).show()
> +-----+----+-------------+
> | name|RAND|RAND_PLUS_TEN|
> +-----+----+-------------+
> |hello|  68|           78|
> +-----+----+-------------+
> {code}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org