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Posted to mapreduce-dev@hadoop.apache.org by "Arun C Murthy (JIRA)" <ji...@apache.org> on 2009/10/24 20:40:59 UTC
[jira] Resolved: (MAPREDUCE-1144) JT should not hold lock while
writing history to DFS
[ https://issues.apache.org/jira/browse/MAPREDUCE-1144?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Arun C Murthy resolved MAPREDUCE-1144.
--------------------------------------
Resolution: Duplicate
Already fixed in MAPREDUCE-816.
> JT should not hold lock while writing history to DFS
> ----------------------------------------------------
>
> Key: MAPREDUCE-1144
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1144
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobtracker
> Affects Versions: 0.20.1
> Reporter: Todd Lipcon
>
> I've seen behavior a few times now where the DFS is being slow for one reason or another, and the JT essentially locks up waiting on it while one thread tries for a long time to write history files out. The stack trace blocking everything is:
> Thread 210 (IPC Server handler 10 on 7277):
> State: WAITING
> Blocked count: 171424
> Waited count: 1209604
> Waiting on java.util.LinkedList@407dd154
> Stack:
> java.lang.Object.wait(Native Method)
> java.lang.Object.wait(Object.java:485)
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.flushInternal(DFSClient.java:3122)
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.closeInternal(DFSClient.java:3202)
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.close(DFSClient.java:3151)
> org.apache.hadoop.fs.FSDataOutputStream$PositionCache.close(FSDataOutputStream.java:67)
> org.apache.hadoop.fs.FSDataOutputStream.close(FSDataOutputStream.java:106)
> sun.nio.cs.StreamEncoder.implClose(StreamEncoder.java:301)
> sun.nio.cs.StreamEncoder.close(StreamEncoder.java:130)
> java.io.OutputStreamWriter.close(OutputStreamWriter.java:216)
> java.io.BufferedWriter.close(BufferedWriter.java:248)
> java.io.PrintWriter.close(PrintWriter.java:295)
> org.apache.hadoop.mapred.JobHistory$JobInfo.logFinished(JobHistory.java:1349)
> org.apache.hadoop.mapred.JobInProgress.jobComplete(JobInProgress.java:2167)
> org.apache.hadoop.mapred.JobInProgress.completedTask(JobInProgress.java:2111)
> org.apache.hadoop.mapred.JobInProgress.updateTaskStatus(JobInProgress.java:873)
> org.apache.hadoop.mapred.JobTracker.updateTaskStatuses(JobTracker.java:3598)
> org.apache.hadoop.mapred.JobTracker.processHeartbeat(JobTracker.java:2792)
> org.apache.hadoop.mapred.JobTracker.heartbeat(JobTracker.java:2581)
> sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
> We should try not to do external IO while holding the JT lock, and instead write the data to an in-memory buffer, drop the lock, and then write.
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