[
https://issues.apache.org/jira/browse/SPARK-23666?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Wenchen Fan resolved SPARK-23666.
---------------------------------
Resolution: Fixed
Assignee: Takeshi Yamamuro
Fix Version/s: 2.4.0
> Undeterministic column name with UDFs
> -------------------------------------
>
> Key: SPARK-23666
> URL: https://issues.apache.org/jira/browse/SPARK-23666
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.2.0, 2.3.0
> Reporter: Daniel Darabos
> Assignee: Takeshi Yamamuro
> Priority: Minor
> Fix For: 2.4.0
>
>
> When you access structure fields in Spark SQL, the auto-generated result
> column name includes an internal ID.
> {code:java}
> scala> import spark.implicits._
> scala> Seq(((1, 2), 3)).toDF("a", "b").createOrReplaceTempView("x")
> scala> spark.udf.register("f", (a: Int) => a)
> scala> spark.sql("select f(a._1) from x").show
> +---------------------+
> |UDF:f(a._1 AS _1#148)|
> +---------------------+
> | 1|
> +---------------------+
> {code}
> This ID ({{#148}}) is only included for UDFs.
> {code:java}
> scala> spark.sql("select factorial(a._1) from x").show
> +-----------------------+
> |factorial(a._1 AS `_1`)|
> +-----------------------+
> | 1|
> +-----------------------+
> {code}
> The internal ID is different on every invocation. The problem this causes for
> us is that the schema of the SQL output is never the same:
> {code:java}
> scala> spark.sql("select f(a._1) from x").schema ==
> spark.sql("select f(a._1) from x").schema
> Boolean = false
> {code}
> We rely on similar schema checks when reloading persisted data.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
