hadoop pig 版本不兼容问题
在Hadoop2.3.0和pig0.12.0安装完后，运行过程中，hadoop和pig grunt均运行正常但是dump数据报下面的错误：
ERROR 1066: Unable to open iterator for alias actor
org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1066: Unable to open iterator for alias actor
at org.apache.pig.PigServer.openIterator(PigServer.java:880)
at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:774)
at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:372)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:198)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:173)
at org.apache.pig.tools.grunt.Grunt.run(Grunt.java:69)
at org.apache.pig.Main.run(Main.java:541)
at org.apache.pig.Main.main(Main.java:156)
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.hadoop.util.RunJar.main(RunJar.java:212)
Caused by: java.io.IOException: Job terminated with anomalous status FAILED
at org.apache.pig.PigServer.openIterator(PigServer.java:872)
... 12 more
导致问题出现的原因是pig已经编译的jar文件和hadoop的版本不兼容导致的，可以采用重新编译的方法解决问题，如下所示：
(1) cd ${PIG_HOME}
(2) mv pig-0.12.0-withouthadoop.jar pig-0.12.0-withouthadoop.jar.bak
(3) mv pig-0.12.0.jar pig-0.12.0.jar.bak
(4) ant clean jar-withouthadoop -Dhadoopversion=23
编译完成后将在${PIG_HOME}/build目錄下生成：
pig-0.12.0-SNAPSHOT.jar, pig-0.12.0-SNAPSHOT-withouthadoop.jar
(5) 将上一步生成的两个文件Copy至${PIG_HOME}下，并进行改名：
pig-0.12.0-SNAPSHOT.jar --> pig-0.12.0.jar
pig-0.12.0-SNAPSHOT-withouthadoop.jar --> pig-0.12.0-withouthadoop.jar