小编Ira*_*ati的帖子

我是Hadoop的新手，并尝试使用Hadoop编写关系联接。该算法尝试在两个连续的回合中加入三个关系。我使用了递归方法。该程序运行正常。但是在执行过程中，它尝试打印如下警告：

14/12/02 10:41:16 WARN io.ReadaheadPool: Failed readahead on ifile                                                                                                                  
EBADF: Bad file descriptor                                                                                                                                                          
        at org.apache.hadoop.io.nativeio.NativeIO$POSIX.posix_fadvise(Native Method)                                                                                                
        at org.apache.hadoop.io.nativeio.NativeIO$POSIX.posixFadviseIfPossible(NativeIO.java:263)                                                                                   
        at org.apache.hadoop.io.nativeio.NativeIO$POSIX$CacheManipulator.posixFadviseIfPossible(NativeIO.java:142)                                                                  
        at org.apache.hadoop.io.ReadaheadPool$ReadaheadRequestImpl.run(ReadaheadPool.java:206)                                                                                      
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)                                                                                          
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)                                                                                          
        at java.lang.Thread.run(Thread.java:745)

这很烦人，我想知道问题的原因以及如何消除它们。我的代码如下：

public class Recursive {  
    /**
     * Join three relations together using recursive method
     * R JOIN S JOIN T = ((R JOIN S) JOIN T)
     */
    static String[] relationSequence;           // Keeps sequence of relations in join
    static int round;                           // Round number running
    /**
     * Mapper
     * Relation name = R …