GitHub user maropu opened a pull request:
https://github.com/apache/spark/pull/16605
[SPARK-18884][SQL] Support Array[_] in ScalaUDF
## What changes were proposed in this pull request?
This pr is to support `Array[_]` in `ScalaUDF`.
Currently, a query below throws an exception if we use the type in
`ScalaUDF`;
```
scala> import org.apache.spark.sql.execution.debug._
scala> Seq((0, 1)).toDF("a", "b").select(array($"a",
$"b").as("ar")).write.mode("overwrite").parquet("/Users/maropu/Desktop/data/")
scala> val df = spark.read.load("/Users/maropu/Desktop/data/")
scala> val df = Seq((0, 1)).toDF("a", "b").select(array($"a",
$"b").as("ar"))
scala> val testArrayUdf = udf { (ar: Array[Int]) => ar.sum }
scala> df.select(testArrayUdf($"ar")).show
Caused by: java.lang.ClassCastException:
scala.collection.mutable.WrappedArray$ofRef cannot be cast to [I
at $anonfun$1.apply(<console>:23)
at
org.apache.spark.sql.catalyst.expressions.ScalaUDF$$anonfun$2.apply(ScalaUDF.scala:89)
at
org.apache.spark.sql.catalyst.expressions.ScalaUDF$$anonfun$2.apply(ScalaUDF.scala:88)
at
org.apache.spark.sql.catalyst.expressions.ScalaUDF.eval(ScalaUDF.scala:1069)
... 99 more
```
On the other hand, another query below is passed;
```
scala> val testSeqUdf = udf { (ar: Seq[Int]) => ar.sum }
scala> df.select(testSeqUdf($"ar")).show
+-------+
|UDF(ar)|
+-------+
| 1|
+-------+
```
The existing implementation checks argument types (`DataType`)ãby
reflection (`ScalaReflection.schemaFor`) in `sql.functions.udf`, and then
creates type converters (`CatalystTypeConverters`) from the types.ã`Seq[_]`
and `Array[_]` are represented as `ArrayType` in `DataType` and both types are
handled by using `ArrayConverter`.ãSo, since it cannot tell a difference
between both types in `DataType`. This pr modified code to create type
converters directly from `TypeTag` in `sql.functions.udf` (and also in
`UDFRegistration.register`).
## How was this patch tested?
Added tests in `DataFrameSuite`.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/maropu/spark SPARK-18884
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/16605.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #16605
----
commit f2cf910813adbcc139deea18c12b99b1a85affbe
Author: Takeshi YAMAMURO <[email protected]>
Date: 2016-12-15T11:24:13Z
Support ArrayType in ScalaUDF
----
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