将DataFrame保存到Spark中的TFRecords时出错

问题描述

我正在尝试将数据帧保存到spark-shell中的TFrecord文件中，这需要spark-tensorflow-connector jar的依赖关系，所以我运行了

spark-shell --jars xxx/xxx/spark-tensorflow-connector_2.11-1.11.0.jar

然后在spark-shell中运行以下代码：

scala> import org.apache.spark.sql.{DataFrame,SaveMode,SparkSession}
import org.apache.spark.sql.{DataFrame,SparkSession}

scala> val df = Seq((8,"bat"),(8,"abc"),(1,"xyz"),(2,"aaa")).toDF("number","word")
df: org.apache.spark.sql.DataFrame = [number: int,word: string]

scala> df.show
+------+----+
|number|word|
+------+----+
|     8| bat|
|     8| abc|
|     1| xyz|
|     2| aaa|
+------+----+

scala> var s = df.write.mode(SaveMode.Overwrite).format("tfrecords").option("recordType","Example")
s: org.apache.spark.sql.DataFrameWriter[org.apache.spark.sql.Row] = org.apache.spark.sql.DataFrameWriter@da1382f

scala> s.save("tmp/tfrecords")
java.lang.NoClassDefFoundError: scala/Product$class                             
  at org.tensorflow.spark.datasources.tfrecords.TensorflowRelation.<init>(TensorflowRelation.scala:29)
  at org.tensorflow.spark.datasources.tfrecords.DefaultSource.createRelation(DefaultSource.scala:78)
  at org.apache.spark.sql.execution.datasources.SaveIntoDataSourceCommand.run(SaveIntoDataSourceCommand.scala:46)
  at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult$lzycompute(commands.scala:70)
  at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult(commands.scala:68)
  at org.apache.spark.sql.execution.command.ExecutedCommandExec.doExecute(commands.scala:90)
  at org.apache.spark.sql.execution.SparkPlan.$anonfun$execute$1(SparkPlan.scala:175)
  at org.apache.spark.sql.execution.SparkPlan.$anonfun$executeQuery$1(SparkPlan.scala:213)
  at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
  at org.apache.spark.sql.execution.SparkPlan.executeQuery(SparkPlan.scala:210)
  at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:171)
  at org.apache.spark.sql.execution.QueryExecution.toRdd$lzycompute(QueryExecution.scala:122)
  at org.apache.spark.sql.execution.QueryExecution.toRdd(QueryExecution.scala:121)
  at org.apache.spark.sql.DataFrameWriter.$anonfun$runCommand$1(DataFrameWriter.scala:944)
  at org.apache.spark.sql.execution.SQLExecution$.$anonfun$withNewExecutionId$5(SQLExecution.scala:100)
  at org.apache.spark.sql.execution.SQLExecution$.withSQLConfPropagated(SQLExecution.scala:160)
  at org.apache.spark.sql.execution.SQLExecution$.$anonfun$withNewExecutionId$1(SQLExecution.scala:87)
  at org.apache.spark.sql.SparkSession.withActive(SparkSession.scala:763)
  at org.apache.spark.sql.execution.SQLExecution$.withNewExecutionId(SQLExecution.scala:64)
  at org.apache.spark.sql.DataFrameWriter.runCommand(DataFrameWriter.scala:944)
  at org.apache.spark.sql.DataFrameWriter.saveToV1Source(DataFrameWriter.scala:396)
  at org.apache.spark.sql.DataFrameWriter.save(DataFrameWriter.scala:380)
  at org.apache.spark.sql.DataFrameWriter.save(DataFrameWriter.scala:269)
  ... 47 elided
Caused by: java.lang.ClassNotFoundException: scala.Product$class
  at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
  at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
  ... 70 more

Spark版本为3.0.0，使用Using Scala版本2.12.10（Java HotSpot（TM）64位服务器VM，Java 1.8.0_261）

解决方法

问题是您正在使用由Scala 2.11编译的Tensorflow连接器（请注意jar名称中的_2.11部分）与由Scala 2.12编译的Spark 3.0。

截至目前，还没有针对Spark 3.0编译的Tensorflow连接器，因此您需要使用由Scala 2.11编译的Spark 2.4.6。