我正在使用Spark 1.5。
我有两个格式的数据框:
scala> libriFirstTable50Plus3DF
res1: org.apache.spark.sql.DataFrame = [basket_id: string, family_id: int]
scala> linkPersonItemLessThan500DF
res2: org.apache.spark.sql.DataFrame = [person_id: int, family_id: int]
libriFirstTable50Plus3DF
有 766,151条记录,而linkPersonItemLessThan500DF
有 26,694,353条记录。请注意,我在repartition(number)
上使用linkPersonItemLessThan500DF
,因为我打算稍后加入这两个。我正在跟进以上代码:
val userTripletRankDF = linkPersonItemLessThan500DF
.join(libriFirstTable50Plus3DF, Seq("family_id"))
.take(20)
.foreach(println(_))
我得到了这个输出:
16/12/13 15:07:10 INFO scheduler.TaskSetManager: Finished task 172.0 in stage 3.0 (TID 473) in 520 ms on mlhdd01.mondadori.it (199/200)
java.util.concurrent.TimeoutException: Futures timed out after [300 seconds]
at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:219)
at scala.concurrent.impl.Promise$DefaultPromise.result(Promise.scala:223)
at scala.concurrent.Await$$anonfun$result$1.apply(package.scala:107)
at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala: at scala.concurrent.Await$.result(package.scala:107)
at org.apache.spark.sql.execution.joins.BroadcastHashJoin.doExecute(BroadcastHashJoin.scala:110)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:140)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:138)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:138)
at org.apache.spark.sql.execution.TungstenProject.doExecute(basicOperators.scala:86)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:140)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:138)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:138)
at org.apache.spark.sql.execution.ConvertToSafe.doExecute(rowFormatConverters.scala:63)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:140)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$5.apply(SparkPlan.scala:138)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:138)
at org.apache.spark.sql.execution.SparkPlan.executeTake(SparkPlan.scala:190)
at org.apache.spark.sql.execution.Limit.executeCollect(basicOperators.scala:207)
at org.apache.spark.sql.DataFrame$$anonfun$collect$1.apply(DataFrame.scala:1386)
at org.apache.spark.sql.DataFrame$$anonfun$collect$1.apply(DataFrame.scala:1386)
at org.apache.spark.sql.execution.SQLExecution$.withNewExecutionId(SQLExecution.scala:56)
at org.apache.spark.sql.DataFrame.withNewExecutionId(DataFrame.scala:1904)
at org.apache.spark.sql.DataFrame.collect(DataFrame.scala:1385)
at org.apache.spark.sql.DataFrame.head(DataFrame.scala:1315)
at org.apache.spark.sql.DataFrame.take(DataFrame.scala:1378)
at org.apache.spark.sql.DataFrame.showString(DataFrame.scala:178)
at org.apache.spark.sql.DataFrame.show(DataFrame.scala:402)
at org.apache.spark.sql.DataFrame.show(DataFrame.scala:363)
at org.apache.spark.sql.DataFrame.show(DataFrame.scala:371)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:72)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:77)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:79)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:81)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:83)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:85)
at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:87)
at $iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:89)
at $iwC$$iwC$$iwC$$iwC.<init>(<console>:91)
at $iwC$$iwC$$iwC.<init>(<console>:93)
at $iwC$$iwC.<init>(<console>:95)
at $iwC.<init>(<console>:97)
at <init>(<console>:99)
at .<init>(<console>:103)
at .<clinit>(<console>)
at .<init>(<console>:7)
at .<clinit>(<console>)
at $print(<console>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:1065)
at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1340)
at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:840)
at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:871)
at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:819)
at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:857)
at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:902)
at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:814)
at org.apache.spark.repl.SparkILoop.processLine$1(SparkILoop.scala:657)
at org.apache.spark.repl.SparkILoop.innerLoop$1(SparkILoop.scala:665)
at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$loop(SparkILoop.scala:670)
at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply$mcZ$sp(SparkILoop.scala:997)
at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945)
at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945)
at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$process(SparkILoop.scala:945)
at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:1059)
at org.apache.spark.repl.Main$.main(Main.scala:31)
at org.apache.spark.repl.Main.main(Main.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:672)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:180)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:205)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:120)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
我不明白这是什么问题。是否像增加等待时间一样简单?加入过于密集吗?我需要更多内存吗?混乱密集吗?有人可以帮忙吗?
答案 0 :(得分:54)
发生这种情况是因为Spark尝试进行广播散列连接,其中一个DataFrame非常大,因此发送它会消耗很多时间。
你可以:
spark.sql.broadcastTimeout
以增加超时时间 - spark.conf.set("spark.sql.broadcastTimeout", newValueForExample36000)
persist()
两个DataFrame,然后Spark将使用Shuffle Join - 来自here 在PySpark中,您可以在以下列方式构建spark上下文时设置配置:
spark = SparkSession
.builder
.appName("Your App")
.config("spark.sql.broadcastTimeout", "36000")
.getOrCreate()
答案 1 :(得分:18)
只需向very concise answer from @T. Gawęda添加一些代码上下文。
在你的星火应用,星火SQL并选择广播哈希联接作为加入,因为的&#34; libriFirstTable50Plus3DF有766151条记录&#34; 的正好是少比所谓的广播阈值(默认为10MB)。
您可以使用spark.sql.autoBroadcastJoinThreshold配置属性控制广播阈值。
spark.sql.autoBroadcastJoinThreshold 配置在执行连接时将广播到所有工作节点的表的最大大小(以字节为单位)。通过将此值设置为-1,可以禁用广播。请注意,目前只有运行命令ANALYZE TABLE COMPUTE STATISTICS noscan的Hive Metastore表支持统计信息。
您可以在堆栈跟踪中找到特定类型的连接:
Spark SQL中的org.apache.spark.sql.execution.joins.BroadcastHashJoin.doExecute(BroadcastHashJoin.scala:110)
BroadcastHashJoin
物理运算符使用broadcast variable将较小的数据集分发给Spark执行程序(而不是随每个任务提供它的副本)。
如果您使用explain
查看了物理查询计划,则会注意到该查询使用BroadcastExchangeExec物理运算符。您可以在此处查看underlying machinery for broadcasting the smaller table(以及超时)。
override protected[sql] def doExecuteBroadcast[T](): broadcast.Broadcast[T] = {
ThreadUtils.awaitResult(relationFuture, timeout).asInstanceOf[broadcast.Broadcast[T]]
}
doExecuteBroadcast
是SparkPlan
合同的一部分,Spark SQL中的每个物理运算符都遵循允许广播(如果需要)。 BroadcastExchangeExec
恰好需要它。
您正在寻找timeout参数。
private val timeout: Duration = {
val timeoutValue = sqlContext.conf.broadcastTimeout
if (timeoutValue < 0) {
Duration.Inf
} else {
timeoutValue.seconds
}
}
正如您所看到的,您可以完全禁用它(使用负值),这意味着等待广播变量无限期地传送给执行程序或使用sqlContext.conf.broadcastTimeout
这正是spark.sql.broadcastTimeout配置属性。您可以在stacktrace中看到默认值5 * 60
秒:
java.util.concurrent.TimeoutException:期货在[300秒]之后超时
答案 2 :(得分:0)
在我的情况下,这是由于在大型数据帧上进行广播引起的:
df.join(broadcast(largeDF))
因此,基于先前的答案,我通过删除广播对其进行了修复:
df.join(largeDF)
答案 3 :(得分:0)
除了增加两个数据帧的spark.sql.broadcastTimeout
或persist()外,
您可以尝试:
1。通过将spark.sql.autoBroadcastJoinThreshold
设置为-1
来禁用广播
2。通过将spark.driver.memory
设置为较高的值来增加火花驱动器的内存。