Konrad Scorciapino created CSV-212:
--------------------------------------
Summary: Empty dataframe being written as an empty CSV, without
header
Key: CSV-212
URL: https://issues.apache.org/jira/browse/CSV-212
Project: Commons CSV
Issue Type: Bug
Affects Versions: 2.0
Reporter: Konrad Scorciapino
Priority: Minor
On Spark 2.1.
How to reproduce:
{{
> $SPARK_HOME/bin/spark-shell
...
scala> import spark.implicits._
import spark.implicits._
scala> val emptyDF = Seq[(Int)]().toDF("foo")
emptyDF: org.apache.spark.sql.DataFrame = [foo: int]
scala> emptyDF.write.option("header","true").csv("/tmp/emptyDF")
scala> spark.read.option("header", "true").csv("/tmp/emptyDF")
java.lang.UnsupportedOperationException: empty collection
at org.apache.spark.rdd.RDD$$anonfun$first$1.apply(RDD.scala:1369)
at
org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
at
org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
at org.apache.spark.rdd.RDD.withScope(RDD.scala:362)
at org.apache.spark.rdd.RDD.first(RDD.scala:1366)
at
org.apache.spark.sql.execution.datasources.csv.CSVFileFormat.findFirstLine(CSVFileFormat.scala:206)
at
org.apache.spark.sql.execution.datasources.csv.CSVFileFormat.inferSchema(CSVFileFormat.scala:60)
at
org.apache.spark.sql.execution.datasources.DataSource$$anonfun$7.apply(DataSource.scala:184)
at
org.apache.spark.sql.execution.datasources.DataSource$$anonfun$7.apply(DataSource.scala:184)
at scala.Option.orElse(Option.scala:289)
at
org.apache.spark.sql.execution.datasources.DataSource.org$apache$spark$sql$execution$datasources$DataSource$$getOrInferFileFormatSchema(DataSource.scala:183)
at
org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:387)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:152)
at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:415)
at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:352)
... 48 elided
scala> :quit
> ls -lh /tmp/emptyDF
>
>
total 0
-rw-r--r-- 1 konrad konrad 0 Jun 19 12:00
part-00000-523374b7-b117-4f36-a428-f43bcb405077.csv
-rw-r--r-- 1 konrad konrad 0 Jun 19 12:00 _SUCCESS
}}
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