异常而连接在火花的MongoDB [英] Exception while connecting to mongodb in spark

问题描述

我得到java.lang.IllegalStateException：没有准备好，在org.bson.BasicBSONDe coder._de code，而尝试使用MongoDB的输入RDD：

I get "java.lang.IllegalStateException: not ready" in org.bson.BasicBSONDecoder._decode while trying to use MongoDB as input RDD:

Configuration conf = new Configuration();
conf.set("mongo.input.uri", "mongodb://127.0.0.1:27017/test.input");

JavaPairRDD<Object, BSONObject> rdd = sc.newAPIHadoopRDD(conf, MongoInputFormat.class, Object.class, BSONObject.class);

System.out.println(rdd.count());

我得到的例外是：
14/08/06 9点49分57秒INFO rdd.NewHadoopRDD：输入分裂：

The exception I get is: 14/08/06 09:49:57 INFO rdd.NewHadoopRDD: Input split:

MongoInputSplit{URI=mongodb://127.0.0.1:27017/test.input, authURI=null, min={ "_id" : { "$oid" : "53df98d7e4b0a67992b31f8d"}}, max={ "_id" : { "$oid" : "53df98d7e4b0a67992b331b8"}}, query={ }, sort={ }, fields={ }, notimeout=false} 14/08/06 09:49:57 
WARN scheduler.TaskSetManager: Loss was due to java.lang.IllegalStateException 
java.lang.IllegalStateException: not ready
            at org.bson.BasicBSONDecoder._decode(BasicBSONDecoder.java:139)
            at org.bson.BasicBSONDecoder.decode(BasicBSONDecoder.java:123)
            at com.mongodb.hadoop.input.MongoInputSplit.readFields(MongoInputSplit.java:185)
            at org.apache.hadoop.io.ObjectWritable.readObject(ObjectWritable.java:285)
            at org.apache.hadoop.io.ObjectWritable.readFields(ObjectWritable.java:77)
            at org.apache.spark.SerializableWritable.readObject(SerializableWritable.scala:42)
            at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
            at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:88)
            at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
            at java.lang.reflect.Method.invoke(Method.java:618)
            at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1089)
            at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1962)
            at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1867)
            at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1419)
            at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2059)
            at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1984)
            at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1867)
            at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1419)
            at java.io.ObjectInputStream.readObject(ObjectInputStream.java:420)
            at org.apache.spark.scheduler.ResultTask.readExternal(ResultTask.scala:147)
            at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1906)
            at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1865)
            at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1419)
            at java.io.ObjectInputStream.readObject(ObjectInputStream.java:420)
            at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:63)
            at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:85)
            at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:165)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1156)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:626)
            at java.lang.Thread.run(Thread.java:804)

所有程序的输出是这里

环境：

• 红帽


• 星火1.0.1


• 的Hadoop 2.4.1


• MongoDB的2.4.10


• 蒙戈-Hadoop的1.3

推荐答案

我想我已经找到了问题：MongoDB的-的Hadoop在其BSON EN codeR /德codeR实例的静态修饰符核心/ src目录/主/ JAVA / COM / MongoDB的/ Hadoop的/输入/ MongoInputSplit.java。当Spark在多​​线程模式下运行的所有线程尝试使用deserialise在相同 EN codeR /德codeR实例，predicatbly有坏的结果。

I think I've found the issue: mongodb-hadoop has a "static" modifier on its BSON encoder/decoder instances in core/src/main/java/com/mongodb/hadoop/input/MongoInputSplit.java. When Spark runs in multithreaded mode all the threads try and deserialise using the same encoder/decoder instances, which predicatbly has bad results.

补丁在我github上这里
（已提交pull请求上游）

Patch on my github here (have submitted a pull request upstream)

我现在可以运行一个8核多线程的火花>蒙戈集合计数（）从Python的！

I'm now able to run an 8 core multithreaded Spark->mongo collection count() from Python!

这篇关于异常而连接在火花的MongoDB的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！