Hi Juan
I have written various applications for continuous processing of csv files.
Please post your entire code and how you are mapping. It becomes easy to
highlight the issue.
Thanks
Ravi Pullareddy
*From:* Juan Rodríguez Hortalá <juan.rodriguez.hort...@gmail.com>
*Sent:* Sunday, 19 April 2020 6:25 PM
*To:* users@zeppelin.apache.org
*Subject:* Re: Serialization issues with case classes with Flink
Just for the record, the Spark version of that works fine:
```
%spark
case class C2(x: Int)
val xs = sc.parallelize(1 to 10)
val csSpark = xs.map{C2(_)}
csSpark.collect
res3: Array[C2] = Array(C2(1), C2(2), C2(3), C2(4), C2(5), C2(6), C2(7),
C2(8), C2(9), C2(10))
```
Thanks,
Juan
On Sun, Apr 19, 2020 at 10:15 AM Juan Rodríguez Hortalá <
juan.rodriguez.hort...@gmail.com> wrote:
Minimal reproduction:
- Fist option
```scala
case class C(x: Int)
val xs = benv.fromCollection(1 to 10)
val cs = xs.map{C(_)}
cs.count
```
defined class C xs: org.apache.flink.api.scala.DataSet[Int] =
org.apache.flink.api.scala.DataSet@39c713c6 cs:
org.apache.flink.api.scala.DataSet[C] =
org.apache.flink.api.scala.DataSet@205a35a
java.lang.IllegalArgumentException: requirement failed: The class C is an
instance class, meaning it is not a member of a toplevel object, or of an
object contained in a toplevel object, therefore it requires an outer
instance to be instantiated, but we don't have a reference to the outer
instance. Please consider changing the outer class to an object. at
scala.Predef$.require(Predef.scala:224) at
org.apache.flink.api.scala.typeutils.ScalaCaseClassSerializer$.lookupConstructor(ScalaCaseClassSerializer.scala:90)
at
org.apache.flink.api.scala.typeutils.ScalaCaseClassSerializer.<init>(ScalaCaseClassSerializer.scala:46)
... 125 elided
- Second option
```scala
object Types {
case class C(x: Int)
}
val cs2 = xs.map{Types.C(_)}
cs2.count
```
defined object Types org.apache.flink.api.common.InvalidProgramException:
Task not serializable at
org.apache.flink.api.scala.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:408)
at
org.apache.flink.api.scala.ClosureCleaner$.org$apache$flink$api$scala$ClosureCleaner$$clean(ClosureCleaner.scala:400)
at
org.apache.flink.api.scala.ClosureCleaner$.clean(ClosureCleaner.scala:168)
at org.apache.flink.api.scala.DataSet.clean(DataSet.scala:125) at
org.apache.flink.api.scala.DataSet$$anon$1.<init>(DataSet.scala:489) at
org.apache.flink.api.scala.DataSet.map(DataSet.scala:488) ... 106 elided
Caused by: java.io.NotSerializableException:
org.apache.flink.api.scala.DataSet at
java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184) at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
Greetings,
Juan
On Sun, Apr 19, 2020 at 10:05 AM Juan Rodríguez Hortalá <
juan.rodriguez.hort...@gmail.com> wrote:
Hi,
I'm using the Flink interpreter and the benv environment. I'm reading some
csv files using benv.readCsvFile and it works ok. I have also defined a
case class C for the csv records. The problem happens when I apply a
map operation on the DataSet of tuples returned by benv.readCsvFile, to
convert it into a DataSet[C].
- If I define the case class C in some cell I get this error:
java.lang.IllegalArgumentException: requirement failed: The class C is an
instance class, meaning it is not a member of a toplevel object, or of an
object contained in a toplevel object, therefore it requires an outer
instance to be instantiated, but we don't have a reference to the outer
instance. Please consider changing the outer class to an object.
- That sounds related to this
https://stackoverflow.com/questions/36042720/case-class-serialazation-in-flink,
it looks like the zeppelin flink interpreter is wrapping the case class
definition as an inner class. I tried defining the case class C inside an
object Types that I define in another cell. With that I also get a
serialization exception.
org.apache.flink.api.common.InvalidProgramException: Task not serializable
org.apache.flink.api.scala.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:408)
org.apache.flink.api.scala.ClosureCleaner$.org$apache$flink$api$scala$ClosureCleaner$$clean(ClosureCleaner.scala:400)
org.apache.flink.api.scala.ClosureCleaner$.clean(ClosureCleaner.scala:168)
org.apache.flink.api.scala.DataSet.clean(DataSet.scala:125)
org.apache.flink.api.scala.DataSet$$anon$1.<init>(DataSet.scala:489)
org.apache.flink.api.scala.DataSet.map(DataSet.scala:488)
$line163.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$$$82b5b23cea489b2712a1db46c77e458$$$$w$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw.liftedTree1$1(<console>:135)
$line163.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$$$82b5b23cea489b2712a1db46c77e458$$$$w$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw.<init>(<console>:133)
I guess that didn't work because the object Types is still defined inside
some class implicitly defined by the interpreter.
Any thoughs about how can I fix this? Also, I understand $line163 etc refer
to the code in the cells, is there some convention I can use to understand
to which line in the notebook those error messages are referring to?
Thanks in advance,
Juan
