Spark設置Kryo序列化緩衝區大小

背景

今天在開發SparkRDD的過程當中出現Buffer Overflow錯誤，查看具體Yarn日誌後發現是由於Kryo序列化緩衝區溢出了，日誌建議調大spark.kryoserializer.buffer.max的value，搜索了一下設置keyo序列化緩衝區的方法，特此整理記錄下來。

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：經過conf參數設置spark.kryoserializer.buffer.max

spark-submit在提交spark做業時能夠帶不少參數，其中有一個參數--conf能夠設置spark.kryoserializer.buffer.max的大小，具體以下。

./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序列化緩衝區的buffer大小設置爲512mb。

方法二：經過程序中拿到sparkConf對象設置spark.kryoserializer.buffer.max

1.設置Kryo爲序列化類

//設置Kryo爲序列化類（默認爲Java序列類）
sparkConf.set("spark.serializer", "org.apache.spark.serializer.KryoSerializer");

2.設置spark.kryoserializer.buffer.max的值

//兩種設置方法
sparkConf.set("spark.kryoserializer.buffer.max", "128m");
sparkConf.set("spark.kryoserializer.buffer.max.mb", "128");

3.檢查是否成功設置Kryo參數

//打印日誌，檢查是否成功設置
System.out.println( sparkConf.get("spark.kryoserializer.buffer.max") );

參考文獻

[1]<a href="https://www.jianshu.com/p/1326199ec3f5" target="_blank">【大數據進擊】如何設置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>

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