Handle large (several MB) text input lines in a reasonable amount of time
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Key: HADOOP-6109
URL: https://issues.apache.org/jira/browse/HADOOP-6109
Project: Hadoop Common
Issue Type: Improvement
Components: util
Affects Versions: 0.19.0
Environment: Linux 2.6 kernel, java 1.6 AMD Dual-Core Opteron 2.6GHz
with 1M L1/L2 cache 1.8G RAM
Reporter: thushara wijeratna
problem:
=======
hadoop was timing out on a simple pass-through job (with the default 10 min
timeout)
cause:
=====
i hunted this down to how Text lines are being processed inside
org.apache.hadoop.util.LineReader.
i have a fix, a task that took more than 20 minutes and still failed to
complete, completes with this fix in under 30 s.
i attach the patch (for trunk)
the problem traces:
================
hadoop version: 0.19.0
userlogs on slave node:
2009-05-29 13:57:33,551 WARN org.apache.hadoop.mapred.TaskRunner: Parent died.
Exiting attempt_200905281652_0013_m_000006_1
[r...@domu-12-31-38-01-7c-92 attempt_200905281652_0013_m_000006_1]#
tellingly, the last input line processed right before this WARN is 19K. (i log
the full input line in the map function for debugging)
output on map-reduce task:
Task attempt_200905281652_0013_m_000006_2 failed to report status for 600
seconds. Killing!
09/05/29 14:08:01 INFO mapred.JobClient: map 99% reduce 32%
09/05/29 14:18:05 INFO mapred.JobClient: map 98% reduce 32%
java.io.IOException: Job failed!
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1217)
at
com.adxpose.data.mr.DailyHeatmapAggregator.run(DailyHeatmapAggregator.java:547)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at
com.adxpose.data.mr.DailyHeatmapAggregator.main(DailyHeatmapAggregator.java:553)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:165)
at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)
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