tez版本：0.5.3
pig版本：0.14.0
解决办法：
将tez.task.scale.memory.reserve-fraction 设置的大点。如下：
set tez.task.scale.memory.reserve-fraction 0.7d ;
报错详情见下：
cause TezChild exit.:java.lang.OutOfMemoryError: Java heap space
at org.apache.tez.runtime.library.common.sort.impl.dflt.DefaultSorter.<init>(DefaultSorter.java:140)
at org.apache.tez.runtime.library.output.OrderedPartitionedKVOutput.start(OrderedPartitionedKVOutput.java:114)
at org.apache.pig.backend.hadoop.executionengine.tez.runtime.PigProcessor.initializeOutputs(PigProcessor.java:299)
at org.apache.pig.backend.hadoop.executionengine.tez.runtime.PigProcessor.run(PigProcessor.java:181)
at org.apache.tez.runtime.LogicalIOProcessorRuntimeTask.run(LogicalIOProcessorRuntimeTask.java:324)
at org.apache.tez.runtime.task.TezTaskRunner$TaskRunnerCallable$1.run(TezTaskRunner.java:176)
at org.apache.tez.runtime.task.TezTaskRunner$TaskRunnerCallable$1.run(TezTaskRunner.java:168)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1796)
at org.apache.tez.runtime.task.TezTaskRunner$TaskRunnerCallable.call(TezTaskRunner.java:168)
at org.apache.tez.runtime.task.TezTaskRunner$TaskRunnerCallable.call(TezTaskRunner.java:163)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)