I run pig in eclipse, pigServer.registerQuery("b = load 'didi1' using org.apache.hcatalog.pig.HCatLoader();"); pigServer.registerQuery("a = order b by id;"); pigServer.getExamples("a"); it run well,but when I run this:pigServer.openIterator("a"); I get error :: org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1066: Unable to open iterator for alias a at org.apache.pig.PigServer.openIterator(PigServer.java:880) at org.gradle.PigHiveHCat.run(PigHiveHCat.java:58) at org.gradle.PigHiveHCat.main(PigHiveHCat.java:22) Caused by: java.io.IOException: Couldn't retrieve job. at org.apache.pig.PigServer.store(PigServer.java:944) at org.apache.pig.PigServer.openIterator(PigServer.java:855) ... 2 more can you help me? all jars are from hadoop、hive、pig clusters.