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https://issues.apache.org/jira/browse/CRUNCH-339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13891617#comment-13891617
]
Josh Wills commented on CRUNCH-339:
-----------------------------------
The most likely cause of that error is a DoFn that contains an instance of the
OryxRecommender class that can't be serialized, not the cache call. Check out
this section of the user guide for options for handling non-serializable
instances inside of DoFn classes:
http://crunch.apache.org/user-guide.html#dovsmap
> java.io.NotSerializableException when calling PCollection.cache()
> -----------------------------------------------------------------
>
> Key: CRUNCH-339
> URL: https://issues.apache.org/jira/browse/CRUNCH-339
> Project: Crunch
> Issue Type: Bug
> Components: IO
> Affects Versions: 0.8.2
> Environment: CDH4.4.0
> Reporter: Sungwoo Park
>
> When I was debugging a MRPipeline, I found that calling cache() function
> causes java.io.NotSerializableException
> Code:
> (...)
> PCollection<Long> candidates = loadCandidate(pipeline, candidatesPath);
> candidates.cache();
> (...)
> public PCollection<Long> loadCandidate(Pipeline p, Path candidatesPath) {
> if(candidatesPath == null)
> return null;
>
> return p.read(From.textFile(candidatesPath)).parallelDo(new
> DoFn<String, Long>(){
> @Override
> public void process(String stringId, Emitter<Long>
> emitter) {
> emitter.emit(Long.parseLong(stringId));
> }
>
> }, Writables.longs());
> }
> Stack trace:
> Exception in thread "main" org.apache.crunch.CrunchRuntimeException:
> java.io.NotSerializableException:
> com.coupang.recommender.ever.utils.recommender.OryxRecommender
> at org.apache.crunch.impl.mr.MRPipeline.plan(MRPipeline.java:104)
> at org.apache.crunch.impl.mr.MRPipeline.runAsync(MRPipeline.java:123)
> at org.apache.crunch.impl.mr.MRPipeline.run(MRPipeline.java:111)
> at
> org.apache.crunch.impl.dist.DistributedPipeline.done(DistributedPipeline.java:109)
> at
> com.coupang.recommender.ever.utils.recommender.OryxRecommender.run(OryxRecommender.java:108)
> at com.coupang.recommender.ever.utils.EverUtil.run(EverUtil.java:30)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
> at com.coupang.recommender.ever.utils.Driver.main(Driver.java:34)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at org.apache.hadoop.util.RunJar.main(RunJar.java:208)
> Caused by: java.io.NotSerializableException:
> com.coupang.recommender.ever.utils.recommender.OryxRecommender
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1164)
> at
> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
> at
> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
> at java.util.ArrayList.writeObject(ArrayList.java:570)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:940)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1469)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
> at
> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
> at java.util.ArrayList.writeObject(ArrayList.java:570)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:940)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1469)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
> at org.apache.crunch.util.DistCache.write(DistCache.java:55)
> at
> org.apache.crunch.impl.mr.plan.JobPrototype.serialize(JobPrototype.java:242)
> at
> org.apache.crunch.impl.mr.plan.JobPrototype.build(JobPrototype.java:215)
> at
> org.apache.crunch.impl.mr.plan.JobPrototype.getCrunchJob(JobPrototype.java:134)
> at org.apache.crunch.impl.mr.plan.MSCRPlanner.plan(MSCRPlanner.java:165)
> at org.apache.crunch.impl.mr.MRPipeline.plan(MRPipeline.java:102)
> ... 12 more
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