Apache Spark: "SparkException: Task not serializable" in spark-shell for RDD manually constructed

Question

我有以下代码可以从事件中检测最常用的顶级域。我用它通过 Spark SQL 获取日期。

功能本身已经过测试并且可以正常工作。我使用 Amazon EMR 和 spark-shell。当 spark 将任务发送到节点时，几乎立即，我收到了一个很长的堆栈跟踪，最后 "SparkException: Task not serializable" 没有任何具体内容。这是怎么回事？

import scala.io.Source
val suffixesStr = 
    Source.fromURL("https://publicsuffix.org/list/public_suffix_list.dat").mkString
val suffList = 
    suffixesStr.lines.filter(line => !line.startsWith("//") && line.trim() != "")
val suffListRDD = sc.parallelize(suffList.toList).collect()

 val cleanDomain = (domain: String) => {
  var secLevelSuffix = 
    suffListRDD.find(suffix => domain.endsWith("."+suffix) && suffix.contains("."))
  var regex = """[^.]+\.[^.]+$""".r
  if (!secLevelSuffix.isEmpty){
    regex = """[^.]+\.[^.]+\.[^.]+$""".r
  }
  var cleanDomain = regex.findFirstMatchIn(domain).map(_ group 0)
  cleanDomain.getOrElse("")
}

val getDomain = (url: String) => {
  val domain = """(?i)^(?:(?:https?):\/\/)?(?:(?:www|www1|www2|www3)\.)?([^:?#/\s]+)""".r.findFirstMatchIn(url).map(_ group 1)
  var res = domain.getOrElse("")
  res = res.toLowerCase()
  if (res.contains("google.com")){
    res = res.replace("google.com.br", "google.com")
  }else{
    res = cleanDomain(res)
  }
  res
}

sqlContext.udf.register("getDomain", getDomain)
val domains = sqlContext.sql("SELECT count(*) c, domain from (SELECT getDomain(page_url) as domain FROM events) t group by domain order by c desc")
domains.take(20).foreach(println)

Answer 1

当您在这种情况下以编程方式定义 RDD 时，不要忘记将不会复制到工作节点的内容标记为 @transient.

你的情况：

@transient val suffixesStr = ...
@transient val suffList = ...

Apache Spark: "SparkException: Task not serializable" in spark-shell for RDD manually constructed

Apache Spark: "SparkException: Task not serializable" in spark-shell for RDD constructed manually

serialization

apache-spark

rdd