You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@spark.apache.org by "Apache Spark (JIRA)" <ji...@apache.org> on 2016/06/06 20:39:21 UTC
[jira] [Assigned] (SPARK-15204) Improve nullability inference for
Aggregator
[ https://issues.apache.org/jira/browse/SPARK-15204?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Apache Spark reassigned SPARK-15204:
------------------------------------
Assignee: (was: Apache Spark)
> Improve nullability inference for Aggregator
> --------------------------------------------
>
> Key: SPARK-15204
> URL: https://issues.apache.org/jira/browse/SPARK-15204
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Environment: spark-2.0.0-SNAPSHOT
> Reporter: koert kuipers
> Priority: Minor
>
> {noformat}
> object SimpleSum extends Aggregator[Row, Int, Int] {
> def zero: Int = 0
> def reduce(b: Int, a: Row) = b + a.getInt(1)
> def merge(b1: Int, b2: Int) = b1 + b2
> def finish(b: Int) = b
> def bufferEncoder: Encoder[Int] = Encoders.scalaInt
> def outputEncoder: Encoder[Int] = Encoders.scalaInt
> }
> val df = List(("a", 1), ("a", 2), ("a", 3)).toDF("k", "v")
> val df1 = df.groupBy("k").agg(SimpleSum.toColumn as "v1")
> df1.printSchema
> df1.show
> root
> |-- k: string (nullable = true)
> |-- v1: integer (nullable = true)
> +---+---+
> | k| v1|
> +---+---+
> | a| 6|
> +---+---+
> {noformat}
> notice how v1 has nullable set to true. the default (and expected) behavior for spark sql is to give an int column false for nullable. for example if i had uses a built-in aggregator like "sum" instead if would have reported nullable = false.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org