Question

我正在学习蜂巢。我已经设置了一个名为records的表。架构如下：

year        : string
temperature : int
quality     : int

以下是示例行

1999 28 3
2000 28 3
2001 30 2

现在我在python中编写了一个示例map reduce脚本，完全按照Hadoop The Definitive Guide一书中的说明进行：

import re
import sys

for line in sys.stdin:
    (year,tmp,q) = line.strip().split()
    if (tmp != '9999' and re.match("[01459]",q)):
        print "%s\t%s" % (year,tmp)

我使用以下命令运行：

ADD FILE /usr/local/hadoop/programs/sample_mapreduce.py;
SELECT TRANSFORM(year, temperature, quality)
USING 'sample_mapreduce.py'
AS year,temperature;

执行失败。在终端上，我得到了这个：

Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2012-08-23 18:30:28,506 Stage-1 map = 0%,  reduce = 0%
2012-08-23 18:30:59,647 Stage-1 map = 100%,  reduce = 100%
Ended Job = job_201208231754_0005 with errors
Error during job, obtaining debugging information...
Examining task ID: task_201208231754_0005_m_000002 (and more) from job job_201208231754_0005
Exception in thread "Thread-103" java.lang.RuntimeException: Error while reading from task log url
    at org.apache.hadoop.hive.ql.exec.errors.TaskLogProcessor.getErrors(TaskLogProcessor.java:130)
    at org.apache.hadoop.hive.ql.exec.JobDebugger.showJobFailDebugInfo(JobDebugger.java:211)
    at org.apache.hadoop.hive.ql.exec.JobDebugger.run(JobDebugger.java:81)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.IOException: Server returned HTTP response code: 400 for URL: http://master:50060/tasklog?taskid=attempt_201208231754_0005_m_000000_2&start=-8193
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1436)
    at java.net.URL.openStream(URL.java:1010)
    at org.apache.hadoop.hive.ql.exec.errors.TaskLogProcessor.getErrors(TaskLogProcessor.java:120)
    ... 3 more

我转到失败的作业列表，这是堆栈跟踪

java.lang.RuntimeException: Hive Runtime Error while closing operators
    at org.apache.hadoop.hive.ql.exec.ExecMapper.close(ExecMapper.java:226)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:57)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:436)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Hit error while closing ..
    at org.apache.hadoop.hive.ql.exec.ScriptOperator.close(ScriptOperator.java:452)
    at org.apache.hadoop.hive.ql.exec.Operator.close(Operator.java:566)
    at org.apache.hadoop.hive.ql.exec.Operator.close(Operator.java:566)
    at org.apache.hadoop.hive.ql.exec.Operator.close(Operator.java:566)
    at org.apache.hadoop.hive.ql.exec.ExecMapper.close(ExecMapper.java:193)
    ... 8 more

相同的痕迹重复了3次。

拜托，有人可以帮我吗？这有什么不对？我完全按照这本书去做。似乎是什么问题。似乎有两个错误。在终端上它表示它无法从任务日志URL中读取。在失败的作业列表中，异常表示不同的内容。请帮忙

Answer 1

我从hadoop管理界面转到stedrr日志，发现python存在语法错误。然后我发现当我创建hive表时，字段分隔符是tab。在split()我没有提到过。所以我将其更改为split('\t')并且工作正常！

Answer 2

只需使用'describe formatted'并在输出底部附近找到'Storage Desc Params：'，它描述了使用的任何分隔符。

python中的示例map reduce脚本用于hive产生异常

2 个答案: