hadoop - 失败的 map task 超出允许的限制，并显示错误:org.apache.pig.data.Typle.isNull()Z

Question

我正在尝试使用CSVExcelStorage()存储Pig对象。我使用的Pig脚本是:

REGISTER /usr/local/pig/lib/piggybank.jar;    
a = LOAD '/input/someText.txt' USING org.apache.pig.piggybank.storage.CSVExcelStorage(',');    
dump a;    
b = FOREACH a GENERATE $1,$2;    
dump b;    
STORE b into '/user/username/b_output' USING org.apache.pig.piggybank.storage.CSVExcelStorage();    

转储给我这个结果

(abcd,efgh,ijkl)    
(mnop,qrst,uvwx)

转储b给我这个结果

(efgh,ijkl)    
(qrst,uvwx)    

但是商店给我这个错误

 ERROR org.apache.pig.tools.pigstats.SimplePigStats - ERROR 2997: Unable to recreate exception from backed error: Error: org.apache.pig.data.Tuple.isNull()Z

 Message: Job failed! Error - # of failed Map Tasks exceeded allowed limit. FailedCount: 1. LastFailedTask: task_201505250503_0003_m_000000

通过浏览器转到JobTracker页面查看错误时，发现以下错误

 Error: org.apache.pig.data.Tuple.isNull()Z

我究竟做错了什么？

Answer 1

我的工作代码:

输入:

1,name1,addr2,atos
2,name2,addr2,barclays
3,name3,addr3,accenture

代码:

REGISTER piggybank.jar;

define CSVExcelStorage org.apache.pig.piggybank.storage.CSVExcelStorage();

a = LOAD '/user/input/data_test3.txt' USING CSVExcelStorage(',');    
--dump a;    
b = FOREACH a GENERATE $1,$2;    
--dump b;    
STORE b into '/user/input/output' USING CSVExcelStorage(); 

输出:

name1,addr2
name2,addr2
name3,addr3