Spark:广播对象时内存不足

Spark: out of memory when broadcasting objects

我试图广播一个不太大的地图(以文本文件形式保存到 HDFS 时约为 70 MB),但我遇到了内存不足的错误。我尝试将驱动程序内存增加到11G,执行程序内存增加到11G,仍然出现同样的错误。 memory.fraction设置为0.3,缓存的数据也不多(小于1G)。

当地图只有 2 MB 左右时,没有问题。我想知道广播对象时是否有大小限制。我怎样才能使用更大的地图解决这个问题?谢谢!

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.IdentityHashMap.resize(IdentityHashMap.java:469)
    at java.util.IdentityHashMap.put(IdentityHashMap.java:445)
    at org.apache.spark.util.SizeEstimator$SearchState.enqueue(SizeEstimator.scala:159)
    at org.apache.spark.util.SizeEstimator$.visitArray(SizeEstimator.scala:229)
    at org.apache.spark.util.SizeEstimator$.visitSingleObject(SizeEstimator.scala:194)
    at org.apache.spark.util.SizeEstimator$.org$apache$spark$util$SizeEstimator$$estimate(SizeEstimator.scala:186)
    at org.apache.spark.util.SizeEstimator$.estimate(SizeEstimator.scala:54)
    at org.apache.spark.util.collection.SizeTracker$class.takeSample(SizeTracker.scala:78)
    at org.apache.spark.util.collection.SizeTracker$class.afterUpdate(SizeTracker.scala:70)
    at org.apache.spark.util.collection.SizeTrackingVector.$plus$eq(SizeTrackingVector.scala:31)
    at org.apache.spark.storage.MemoryStore.unrollSafely(MemoryStore.scala:278)
    at org.apache.spark.storage.MemoryStore.putIterator(MemoryStore.scala:165)
    at org.apache.spark.storage.MemoryStore.putIterator(MemoryStore.scala:143)
    at org.apache.spark.storage.BlockManager.doPut(BlockManager.scala:801)
    at org.apache.spark.storage.BlockManager.putIterator(BlockManager.scala:648)
    at org.apache.spark.storage.BlockManager.putSingle(BlockManager.scala:1006)
    at org.apache.spark.broadcast.TorrentBroadcast.writeBlocks(TorrentBroadcast.scala:99)
    at org.apache.spark.broadcast.TorrentBroadcast.<init>(TorrentBroadcast.scala:85)
    at org.apache.spark.broadcast.TorrentBroadcastFactory.newBroadcast(TorrentBroadcastFactory.scala:34)
    at org.apache.spark.broadcast.BroadcastManager.newBroadcast(BroadcastManager.scala:63)
    at org.apache.spark.SparkContext.broadcast(SparkContext.scala:1327)

编辑: 根据评论补充更多信息:

广播相关的一些代码:

val mappingAllLocal: Map[String, Int] = mappingAll.rdd.map(r => (r.getAs[String](0), r.getAs[Int](1))).collectAsMap().toMap
// I can use the above mappingAll to HDFS, and it's around 70MB
val mappingAllBrd = sc.broadcast(mappingAllLocal) // <-- this is where the out of memory happens

您可以尝试增加 JVM 堆大小:

-Xmx2g : max size of 2Go
-Xms2g : initial size of 2Go (default size is 256mo)

使用set("spark.driver.memory", "15G")对客户端模式没有影响。您必须在提交申请时使用命令行参数--conf="spark.driver.memory=15G"以增加驱动程序的堆大小。