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https://issues.apache.org/jira/browse/MAPREDUCE-6024?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14095217#comment-14095217
]
Zhijie Shen commented on MAPREDUCE-6024:
----------------------------------------
bq. It's necessary to multiply the failures by numMaps. Because when
SocketTimeoutException happened, copyFailed will add numMaps to hostFailures.
It seems not to be clear to me. The current code is:
{code}
} catch (IOException ie) {
boolean connectExcpt = ie instanceof ConnectException;
ioErrs.increment(1);
LOG.warn("Failed to connect to " + host + " with " + remaining.size() +
" map outputs", ie);
// If connect did not succeed, just mark all the maps as failed,
// indirectly penalizing the host
for(TaskAttemptID left: remaining) {
scheduler.copyFailed(left, host, false, connectExcpt);
}
// Add back all the remaining maps, WITHOUT marking them as failed
for(TaskAttemptID left: remaining) {
scheduler.putBackKnownMapOutput(host, left);
}
return;
}
{code}
Once SocketTimeoutException occurs, copyFailed will be invoked for
remaining.size times, and each time hostFailures of this particular mapHost
will be increased by 1. After the iteration is completed, hostFailures is
increased by numMaps. If ActualMaxFailures = maxHostFailures * numMaps, why
not checking it once after the iteration is over?
{code}
for(TaskAttemptID left: failedTasks) {
- scheduler.copyFailed(left, host, true, false);
+ scheduler.copyFailed(left, host, true, false, remaining.size());
}
{code}
In addition, hostFailures will be increased by faliedTasks.size instead of
remaining.size here, won't it? Please correct me if I've missed something.
> java.net.SocketTimeoutException in Fetcher caused jobs stuck for more than 1
> hour
> ---------------------------------------------------------------------------------
>
> Key: MAPREDUCE-6024
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6024
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: mr-am, task
> Reporter: zhaoyunjiong
> Assignee: zhaoyunjiong
> Priority: Critical
> Attachments: MAPREDUCE-6024.1.patch, MAPREDUCE-6024.2.patch,
> MAPREDUCE-6024.patch
>
>
> 2014-08-04 21:09:42,356 WARN fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.Fetcher: Failed to connect to
> fake.host.name:13562 with 2 map outputs
> java.net.SocketTimeoutException: Read timed out
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:129)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:697)
> at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:640)
> at
> sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1195)
> at
> org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:289)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:165)
> 2014-08-04 21:09:42,360 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl:
> fake.host.name:13562 freed by fetcher#33 in 180024ms
> 2014-08-04 21:09:55,360 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl: Assigning
> fake.host.name:13562 with 3 to fetcher#33
> 2014-08-04 21:09:55,360 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl: assigned 3 of 3
> to fake.host.name:13562 to fetcher#33
> 2014-08-04 21:12:55,463 WARN fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.Fetcher: Failed to connect to
> fake.host.name:13562 with 3 map outputs
> java.net.SocketTimeoutException: Read timed out
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:129)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:697)
> at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:640)
> at
> sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1195)
> at
> org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:289)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:165)
> ...
> 2014-08-04 22:03:13,416 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl:
> fake.host.name:13562 freed by fetcher#33 in 271081ms
> 2014-08-04 22:04:13,417 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl: Assigning
> fake.host.name:13562 with 3 to fetcher#33
> 2014-08-04 22:04:13,417 INFO fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl: assigned 3 of 3
> to fake.host.name:13562 to fetcher#33
> 2014-08-04 22:07:13,449 WARN fetcher#33
> org.apache.hadoop.mapreduce.task.reduce.Fetcher: Failed to connect to
> fake.host.name:13562 with 3 map outputs
> java.net.SocketTimeoutException: Read timed out
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:129)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:697)
> at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:640)
> at
> sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1195)
> at
> org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:289)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:165)
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