I have tried that as well, I get a compile error --
[ERROR] ...SparkProto.java:[105,39] error: no suitable method found for
create(SparkContext,<anonymous
ConnectionFactory>,String,int,int,int,<anonymous
Function<ResultSet,Integer>>)
The code is a copy and paste:
JavaRDD<Integer> jdbcRDD = JdbcRDD.create(
sc,
new JdbcRDD.ConnectionFactory() {
public Connection getConnection() throws SQLException {
return
DriverManager.getConnection("jdbc:derby:target/JavaJdbcRDDSuiteDb");
}
},
"SELECT DATA FROM FOO WHERE ? <= ID AND ID <= ?",
1, 100, 1,
new Function<ResultSet, Integer>() {
public Integer call(ResultSet r) throws Exception {
return r.getInt(1);
}
}
);
The other thing I've tried was to define a static class locally for
GetConnection and use the JdbcCreate constructor. This got around the
compile issues but blew up at runtime with "NoClassDefFoundError:
scala/runtime/AbstractFunction0" !
JdbcRDD<Row> jdbcRDD = new JdbcRDD<Row>(
sc,
(AbstractFunction0<Connection>) new DbConn(), // had to cast or a compile
error
SQL_QUERY,
0L,
1000L,
10,
new MapRow(),
ROW_CLASS_TAG);
// DbConn is defined as public static class DbConn extends
AbstractFunction0<Connection> implements Serializable
On Wed, Feb 18, 2015 at 1:20 PM, Cody Koeninger <c...@koeninger.org> wrote:
> That test I linked
>
>
> https://github.com/apache/spark/blob/v1.2.1/core/src/test/java/org/apache/spark/JavaJdbcRDDSuite.java#L90
>
> is calling a static method JdbcRDD.create, not new JdbcRDD. Is that what
> you tried doing?
>
> On Wed, Feb 18, 2015 at 12:00 PM, Dmitry Goldenberg <
> dgoldenberg...@gmail.com> wrote:
>
>> Thanks, Cody. Yes, I originally started off by looking at that but I get
>> a compile error if I try and use that approach: constructor JdbcRDD in
>> class JdbcRDD<T> cannot be applied to given types. Not to mention that
>> JavaJdbcRDDSuite somehow manages to not pass in the class tag (the last
>> argument).
>>
>> Wonder if it's a JDK version issue, I'm using 1.7.
>>
>> So I've got this, which doesn't compile
>>
>> JdbcRDD<Row> jdbcRDD = new JdbcRDD<Row>(
>> new SparkContext(conf),
>> new JdbcRDD.ConnectionFactory() {
>> public Connection getConnection() throws SQLException {
>> Connection conn = null;
>> try {
>> Class.forName(JDBC_DRIVER);
>> conn = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD);
>> } catch (ClassNotFoundException ex) {
>> throw new RuntimeException("Error while loading JDBC driver.", ex);
>> }
>> return conn;
>> }
>> },
>> "SELECT * FROM EMPLOYEES",
>> 0L,
>> 1000L,
>> 10,
>> new Function<ResultSet, Row>() {
>> public Row call(ResultSet r) throws Exception {
>> return null; // have some actual logic here...
>> }
>> },
>> scala.reflect.ClassManifestFactory$.MODULE$.fromClass(Row.class));
>>
>> The other approach was mimicing the DbConnection class from this post:
>> http://www.sparkexpert.com/2015/01/02/load-database-data-into-spark-using-jdbcrdd-in-java/.
>> It got around any of the compilation issues but then I got the runtime
>> error where Spark wouldn't recognize the db connection class as a
>> scala.Function0.
>>
>>
>>
>> On Wed, Feb 18, 2015 at 12:37 PM, Cody Koeninger <c...@koeninger.org>
>> wrote:
>>
>>> Take a look at
>>>
>>>
>>> https://github.com/apache/spark/blob/v1.2.1/core/src/test/java/org/apache/spark/JavaJdbcRDDSuite.java
>>>
>>>
>>>
>>> On Wed, Feb 18, 2015 at 11:14 AM, dgoldenberg <dgoldenberg...@gmail.com>
>>> wrote:
>>>
>>>> I'm reading data from a database using JdbcRDD, in Java, and I have an
>>>> implementation of Function0<Connection> whose instance I supply as the
>>>> 'getConnection' parameter into the JdbcRDD constructor. Compiles fine.
>>>>
>>>> The definition of the class/function is as follows:
>>>>
>>>> public class GetDbConnection extends AbstractFunction0<Connection>
>>>> implements Serializable
>>>>
>>>> where scala.runtime.AbstractFunction0 extends scala.Function0.
>>>>
>>>> At runtime, I get an exception as below. Does anyone have an idea as to
>>>> how
>>>> to resolve this/work around it? Thanks.
>>>>
>>>> I'm running Spark 1.2.1 built for Hadoop 2.4.
>>>>
>>>>
>>>> Exception in thread "main" org.apache.spark.SparkException: Job aborted
>>>> due
>>>> to stage failure: Task 3 in stage 0.0 failed 1 times, most recent
>>>> failure:
>>>> Lost task 3.0 in stage 0.0 (TID 3, localhost):
>>>> java.lang.ClassCastException:
>>>> cannot assign instance of com.kona.motivis.spark.proto.GetDbConnection
>>>> to
>>>> field
>>>> org.apache.spark.rdd.JdbcRDD.org$apache$spark$rdd$JdbcRDD$$getConnection
>>>> of
>>>> type scala.Function0 in instance of org.apache.spark.rdd.JdbcRDD
>>>> at
>>>>
>>>> java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2083)
>>>> at
>>>> java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1261)
>>>> at
>>>> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1996)
>>>> at
>>>> java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
>>>> at
>>>>
>>>> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
>>>> at
>>>> java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
>>>> at
>>>> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
>>>> at
>>>> java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
>>>> at
>>>>
>>>> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
>>>> at
>>>> java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
>>>> at
>>>> java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
>>>> at
>>>>
>>>> org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:62)
>>>> at
>>>>
>>>> org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:87)
>>>> at
>>>> org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:57)
>>>> at org.apache.spark.scheduler.Task.run(Task.scala:56)
>>>> at
>>>> org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:200)
>>>> at
>>>>
>>>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>>>> at
>>>>
>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>>>> at java.lang.Thread.run(Thread.java:744)
>>>>
>>>> Driver stacktrace:
>>>> at
>>>> org.apache.spark.scheduler.DAGScheduler.org
>>>> $apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1214)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1203)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1202)
>>>> at
>>>>
>>>> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
>>>> at
>>>> scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1202)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:696)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:696)
>>>> at scala.Option.foreach(Option.scala:236)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:696)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGSchedulerEventProcessActor$$anonfun$receive$2.applyOrElse(DAGScheduler.scala:1420)
>>>> at akka.actor.Actor$class.aroundReceive(Actor.scala:465)
>>>> at
>>>>
>>>> org.apache.spark.scheduler.DAGSchedulerEventProcessActor.aroundReceive(DAGScheduler.scala:1375)
>>>> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
>>>> at akka.actor.ActorCell.invoke(ActorCell.scala:487)
>>>> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
>>>> at akka.dispatch.Mailbox.run(Mailbox.scala:220)
>>>> at
>>>>
>>>> akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
>>>> at
>>>> scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
>>>> at
>>>>
>>>> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
>>>> at
>>>> scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
>>>> at
>>>>
>>>> scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://apache-spark-user-list.1001560.n3.nabble.com/JdbcRDD-ClassCastException-with-scala-Function0-tp21707.html
>>>> Sent from the Apache Spark User List mailing list archive at Nabble.com.
>>>>
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>>>>
>>>>
>>>
>>
>
