Pig:合并mapreduce的结果时出错 猪字 猪产量 清管器原木 环境 操作系统：ubuntu 12.04 Hadoop:1.0.4 Subversion-R1393290 清管器：0.11.0（r1446324）

附言：

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如果sim1是从hdfs加载的，则它可以工作，例如，

sim1=load'sim'as（gid1:long，gid2:long，sim:double）

这里的核心错误似乎是CloneNotSupportedExceptions，不幸的是，我无法帮助您对于那些在这里寻找这篇文章的人来说，这是一个很好的选择。

base = load 'u.base' as (uid:long, gid:long, pref:double);
sim1 = mapreduce 'mahout-core-0.7-job.jar'
        store base into 'input'
        load 'output' as (gid1:long, gid2:long, sim:double)
        `org.apache.mahout.cf.taste.hadoop.similarity.item.ItemSimilarityJob -i input -o output -s SIMILARITY_EUCLIDEAN_DISTANCE`;
sim2 = foreach sim1 generate gid2 as gid1, gid1 as gid2, sim;
sim3 = union sim1,sim2;
dump sim3;

2013-03-28 09:21:32,564 [main] INFO  org.apache.pig.tools.pigstats.ScriptState - Pig features used in the script: UNION,NATIVE
2013-03-28 09:21:32,676 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MRCompiler - File concatenation threshold: 100 optimistic? false
2013-03-28 09:21:32,699 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer - MR plan size before optimization: 4
2013-03-28 09:21:32,702 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 2127: Internal Error: Cloning of plan failed for optimization.
Details at logfile: /home/chenwl/logs/pig_1364433685680.log

Pig Stack Trace
---------------
ERROR 2127: Internal Error: Cloning of plan failed for optimization.

org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1066: Unable to open iterator for alias sim3
    at org.apache.pig.PigServer.openIterator(PigServer.java:836)
    at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:696)
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:320)
    at org.apache.pig.tools.grunt.GruntParser.loadScript(GruntParser.java:531)
    at org.apache.pig.tools.grunt.GruntParser.processScript(GruntParser.java:480)
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.Script(PigScriptParser.java:804)
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:449)
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:194)
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:170)
    at org.apache.pig.tools.grunt.Grunt.run(Grunt.java:69)
    at org.apache.pig.Main.run(Main.java:538)
    at org.apache.pig.Main.main(Main.java:157)
    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:156)
Caused by: org.apache.pig.PigException: ERROR 1002: Unable to store alias sim3
    at org.apache.pig.PigServer.storeEx(PigServer.java:935)
    at org.apache.pig.PigServer.store(PigServer.java:898)
    at org.apache.pig.PigServer.openIterator(PigServer.java:811)
    ... 16 more
Caused by: org.apache.pig.impl.plan.optimizer.OptimizerException: ERROR 2127: Internal Error: Cloning of plan failed for optimization.
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer.mergeDiamondMROper(MultiQueryOptimizer.java:304)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer.visitMROp(MultiQueryOptimizer.java:219)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceOper.visit(MapReduceOper.java:273)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceOper.visit(MapReduceOper.java:46)
    at org.apache.pig.impl.plan.ReverseDependencyOrderWalker.walk(ReverseDependencyOrderWalker.java:71)
    at org.apache.pig.impl.plan.PlanVisitor.visit(PlanVisitor.java:46)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer.visit(MultiQueryOptimizer.java:94)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher.compile(MapReduceLauncher.java:617)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher.launchPig(MapReduceLauncher.java:146)
    at org.apache.pig.PigServer.launchPlan(PigServer.java:1264)
    at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:1249)
    at org.apache.pig.PigServer.storeEx(PigServer.java:931)
    ... 18 more
Caused by: java.lang.CloneNotSupportedException: Unable to find clone for op 1-36: Native('hadoop jar mahout-core-0.7-job.jar org.apache.mahout.cf.taste.hadoop.similarity.item.ItemSimilarityJob -i input -o output -s SIMILARITY_EUCLIDEAN_DISTANCE ') - scope-12
    at org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan.clone(PhysicalPlan.java:273)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer.mergeDiamondMROper(MultiQueryOptimizer.java:298)
    ... 29 more
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