Spark SQL - PostgreSQL JDBC Classpath Issues - postgresql

Question

I’m having an issue connecting Spark SQL to a PostgreSQL data source. I’ve downloaded the Postgres JDBC jar and included it in an uber jar using sbt-assembly.
My (failing) source code:
https://gist.github.com/geowa4/a9bc238ca7c372b95267.
I’ve also tried using sqlContext.jdbc() preceded with classOf[org.postgresql.Driver] as well. It appears the driver can access the Driver just fine.
Any help would be much appreciated. Thanks.
SimpleApp.scala:
import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
import org.apache.spark.SparkConf
import org.apache.spark.sql.SQLContext
object SimpleApp {
def main(args: Array[String]) {
val conf = new SparkConf().setAppName("Simple Application")
val sc = new SparkContext(conf)
val sqlContext = new SQLContext(sc)
import sqlContext.implicits._
val commits = sqlContext.load("jdbc", Map(
"url" -> "jdbc:postgresql://192.168.59.103:5432/postgres",
"dbtable" -> "commits",
"driver" -> "org.postgresql.Driver"))
commits.select("message").show(1)
}
}
simple.sbt:
name := "simple-project"
version := "1.0"
scalaVersion := "2.11.6"
libraryDependencies += "org.apache.spark" %% "spark-core" % "1.3.1" % "provided"
libraryDependencies += "org.apache.spark" %% "spark-sql" % "1.3.1" % "provided"
libraryDependencies += "org.postgresql" % "postgresql" % "9.4-1201-jdbc41"
output (Edited):
Exception in thread "main" java.lang.ClassNotFoundException: org.postgresql.Driver
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at org.apache.spark.sql.jdbc.DefaultSource.createRelation(JDBCRelation.scala:102)
at org.apache.spark.sql.sources.ResolvedDataSource$.apply(ddl.scala:219)
at org.apache.spark.sql.SQLContext.load(SQLContext.scala:697)
at SimpleApp$.main(SimpleApp.scala:17)
at SimpleApp.main(SimpleApp.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:569)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:166)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:189)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:110)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
EDIT: I changed the Scala version to 2.10.5 and the output changed to this. I feel like I'm making progress.

Answer 1

There is a problem with general problem with JDBC, where the primordial classloader must know about the jar. In Spark 1.3 this can be addressed using the SPARK_CLASSPATH option as described here:
https://spark.apache.org/docs/1.3.0/sql-programming-guide.html#jdbc-to-other-databases
In Spark 1.4, this should be fixed by #5782.

Answer 2

1) Copy file into your jar location
2) Add jar in path as follows
spark-submit --jars /usr/share/java/postgresql-jdbc.jar --class com.examples.WordCount .. .. ..