This seems to be related to the known and rather long standing issue HADOOP-1374 http://issues.apache.org/jira/browse/HADOOP-1374 Could you please add your comments there. Thanks, --Konstantin
张茂森 wrote: >How large do that files in the INPUT path? > >-----邮件原件----- >发件人: Xiaoguang Qi [mailto:[EMAIL PROTECTED] >发送时间: 2007年9月7日 11:51 >收件人: [email protected] >主题: hadoop hang on reduce > >Hi, all -- > >I was trying to configure hadoop to work on two machines. The dfs >seems to work fine. But when I tried the 'grep' example in >'hadoop-0.13.1-examples.jar', it always hang upon the finish of map >tasks and the start of reduce tasks. I thought this could be a network >problem; so I reconfigured it to run on a single machine, but still >running in distributed mode. The problem remains. Here are the >configuration files. > >========== hadoop-site.xml ========== ><?xml version="1.0"?> ><?xml-stylesheet type="text/xsl" href="configuration.xsl"?> > ><!-- Put site-specific property overrides in this file. --> > ><configuration> > > <property> > <name>fs.default.name</name> > <value>(masked machine name):9000</value> > </property> > > <property> > <name>mapred.job.tracker</name> > <value>(masked machine name):9001</value> > </property> > > <property> > <name>dfs.replication</name> > <value>1</value> > </property> > > <property> > <name>dfs.name.dir</name> > <value>dfs-space/dfs/name</value> > </property> > > <property> > <name>dfs.data.dir</name> > <value>dfs-space/dfs/data</value> > </property> > > <property> > <name>mapred.local.dir</name> > <value>dfs-space/mapred/local</value> > </property> > ></configuration> > > >========== mapred-default.xml ========== ><?xml version="1.0"?> ><?xml-stylesheet type="text/xsl" href="configuration.xsl"?> > ><!-- Put mapred-specific property overrides in this file. --> > ><configuration> > <property> > <name>mapred.map.tasks</name> > <value>20</value> > </property> > > <property> > <name>mapred.reduce.tasks</name> > <value>1</value> > </property> ></configuration> > > >When I run the following command: >bin/hadoop jar hadoop-*-examples.jar grep input output 'dfs[a-z.]+' > >here's what the screen shows: > >07/09/06 23:10:20 INFO mapred.FileInputFormat: Total input paths to process >: 3 >07/09/06 23:10:20 INFO mapred.JobClient: Running job: job_0001 >07/09/06 23:10:21 INFO mapred.JobClient: map 0% reduce 0% >07/09/06 23:10:32 INFO mapred.JobClient: map 4% reduce 0% >07/09/06 23:10:33 INFO mapred.JobClient: map 13% reduce 0% >07/09/06 23:10:34 INFO mapred.JobClient: map 18% reduce 0% >07/09/06 23:10:35 INFO mapred.JobClient: map 22% reduce 0% >07/09/06 23:10:36 INFO mapred.JobClient: map 27% reduce 0% >07/09/06 23:10:37 INFO mapred.JobClient: map 36% reduce 0% >07/09/06 23:10:39 INFO mapred.JobClient: map 45% reduce 0% >07/09/06 23:10:40 INFO mapred.JobClient: map 49% reduce 0% >07/09/06 23:10:41 INFO mapred.JobClient: map 54% reduce 0% >07/09/06 23:10:42 INFO mapred.JobClient: map 59% reduce 0% >07/09/06 23:10:43 INFO mapred.JobClient: map 68% reduce 0% >07/09/06 23:10:45 INFO mapred.JobClient: map 77% reduce 0% >07/09/06 23:10:47 INFO mapred.JobClient: map 86% reduce 0% >07/09/06 23:10:49 INFO mapred.JobClient: map 95% reduce 0% >07/09/06 23:10:50 INFO mapred.JobClient: map 100% reduce 0% > >Then the program hang for a long time until I kill it. >Here's what I find in the 'tasktracker' log file: > >...... >2007-09-06 22:54:52,569 INFO org.apache.hadoop.mapred.TaskTracker: >LaunchTaskAct >ion: task_0001_m_000021_0 >2007-09-06 22:54:53,942 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_m_0 >00019_0 1.0% hdfs://(masked machine name):9000/user/(masked user >name)/input/hadoop-defau >lt.xml:26068+1018 >2007-09-06 22:54:53,944 INFO org.apache.hadoop.mapred.TaskTracker: Task >task_000 >1_m_000019_0 is done. >2007-09-06 22:54:54,040 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_m_0 >00021_0 1.0% hdfs://(masked machine name):9000/user/(masked user >name)/input/hadoop-site. >xml:0+178 >2007-09-06 22:54:54,043 INFO org.apache.hadoop.mapred.TaskTracker: Task >task_000 >1_m_000021_0 is done. >2007-09-06 22:54:54,059 INFO org.apache.hadoop.mapred.TaskTracker: >LaunchTaskAct >ion: task_0001_r_000000_0 >2007-09-06 22:54:55,935 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_r_0 >00000_0 0.0% reduce > copy > >2007-09-06 22:54:56,939 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_r_0 >00000_0 0.0% reduce > copy > >2007-09-06 22:54:57,942 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_r_0 >00000_0 0.0% reduce > copy > >2007-09-06 22:54:58,947 INFO org.apache.hadoop.mapred.TaskTracker: >task_0001_r_0 >00000_0 0.0% reduce > copy > >...... > >The last line repeats until the end of log file. > >Any one have an idea what the problem is? Any suggestion is appreciated! > > >
