java - 转储不适用于 pigrunner

Question

以下是我运行 pigrunner 和 pigstats 的代码:

    String[] args = {"abc.pig"};
    PigStats stats = PigRunner.run(args,null);

    System.out.println("Stats : " + stats.getReturnCode());

    OutputStats os = stats.result("B");

    Iterator<Tuple> it = os.iterator();

    while(it.hasNext()){
        Tuple t = it.next();
        System.out.println(t.getAll());
    }

abc.pig 的内容

A = load 'Courses' using PigStorage(' ');
B = foreach A generate $0 as id;
dump B;

我得到了正确的输出，但紧随其后的是带有根本原因的异常 Stacktrace

org.apache.hadoop.mapreduce.lib.input.InvalidInputException: Input path does not exist: hdfs://localhost:54310/tmp/temp-221133443/tmp1478461116
  at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.listStatus(FileInputFormat.java:235)
  at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigFileInputFormat.listStatus(PigFileInputFormat.java:37)
  at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.getSplits(FileInputFormat.java:252)
  at org.apache.pig.impl.io.ReadToEndLoader.init(ReadToEndLoader.java:154)
  at org.apache.pig.impl.io.ReadToEndLoader.<init>(ReadToEndLoader.java:116)
  at org.apache.pig.tools.pigstats.OutputStats.iterator(OutputStats.java:148)
  at org.apache.jsp.result_jsp._jspService(result_jsp.java:86)
  at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
  at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
  at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
  at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
  at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
  at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
  at java.lang.Thread.run(Thread.java:662)

现在，如果我用 STORE 替换 DUMP，相同的代码可以正常工作。

有人能解释一下这是怎么回事吗？

谢谢拉维

Answer 1

在转储的情况下，Pig 将输出存储在临时 位置，例如:hdfs://localhost/tmp/temp797130848/tmp1101984728(看看你工作的 config.xml 中的 pig.map.output.dirs)

PigRunner.run()电话 GruntParser.processDump(String alias)在迭代结果元组并将它们打印到控制台的过程中的某个时刻:

Iterator<Tuple> result = mPigServer.openIterator(alias);
while (result.hasNext())
{
  Tuple t = result.next();
  System.out.println(TupleFormat.format(t));
}

在此之后，但在返回之前，它还会调用 FileLocalizer.deleteTempFiles()删除这个临时目录。

现在你想返回别名 B 的结果。 OutputStats的迭代器尝试再次打开临时文件以遍历元组作为 PigRunner.run()以前做过。但问题是这个文件不再存在，因此你会得到异常。

所以我建议您删除 System.out.println("Stats : " + stats.getReturnCode()); 之后的代码因为您已经打印出转储。