在为关系运行dump命令时不返回任何记录，它给出:测试文件:学生vineet1hisham2raj3ajeet4sujit5ramesh6priya7priyanka8suresh9ritesh10计数器:Totalrecordswritten:0Totalbyteswritten:0SpillableMemoryManagerspillcount:0Totalbagsproactivelyspilled:0Totalrecordsproactivelyspilled:0但它包含一个数据，请帮我解决这个错误grunt>a=load'/pigdata/student';2016-08-0