Spark设置Kryo序列化缓冲区大小

背景

今天在开发SparkRDD的过程当中出现Buffer Overflow错误，查看具体Yarn日志后发现是由于Kryo序列化缓冲区溢出了，日志建议调大spark.kryoserializer.buffer.max的value，搜索了一下设置keyo序列化缓冲区的方法，特此整理记录下来。

20/01/08 17:12:55 WARN scheduler.TaskSetManager: Lost task 1.0 in stage 1.0 (TID 4, s015.test.com, executor 1): org.apache.spark.SparkException: Kryo serialization failed: Buffer overflow. Available: 0, required: 10300408. To avoid this, increase spark.kryoserializer.buffer.max value.
	at org.apache.spark.serializer.KryoSerializerInstance.serialize(KryoSerializer.scala:315)
	at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:367)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

方法一：经过conf参数设置spark.kryoserializer.buffer.max

spark-submit在提交spark做业时能够带不少参数，其中有一个参数--conf能够设置spark.kryoserializer.buffer.max的大小，具体以下。

./bin/spark-submit \
  --class <main-class> \
  --master <master-url> \
  --deploy-mode <deploy-mode> \
  --conf spark.kryoserializer.buffer.max=512m \
  ... # other options
  <application-jar> \
  [application-arguments]

上面的--conf spark.kryoserializer.buffer.max=512m即表明把Kryo序列化缓冲区的buffer大小设置为512mb。

方法二：经过程序中拿到sparkConf对象设置spark.kryoserializer.buffer.max

1.设置Kryo为序列化类

//设置Kryo为序列化类（默认为Java序列类）
sparkConf.set("spark.serializer", "org.apache.spark.serializer.KryoSerializer");

2.设置spark.kryoserializer.buffer.max的值

//两种设置方法
sparkConf.set("spark.kryoserializer.buffer.max", "128m");
sparkConf.set("spark.kryoserializer.buffer.max.mb", "128");

3.检查是否成功设置Kryo参数

//打印日志，检查是否成功设置
System.out.println( sparkConf.get("spark.kryoserializer.buffer.max") );

参考文献

[1]<a href="https://www.jianshu.com/p/1326199ec3f5" target="_blank">【大数据进击】如何设置spark.kryoserializer.buffer.max value</a> [2]<a href="http://spark.apache.org/docs/latest/submitting-applications.html" target="_blank">Spark official docs: Submitting Applications</a>

原文出处：https://www.cnblogs.com/JasonCeng/p/12169233.html