hadoop-mapreduce-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] [Created] (MAPREDUCE-7128) LocalJobRunner may fail due to metrics name collision
Date Sat, 11 Aug 2018 00:38:00 GMT
Todd Lipcon created MAPREDUCE-7128:
--------------------------------------

             Summary: LocalJobRunner may fail due to metrics name collision
                 Key: MAPREDUCE-7128
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-7128
             Project: Hadoop Map/Reduce
          Issue Type: Bug
            Reporter: Todd Lipcon


Running Hive in local mode, I got the following failure:
{code}
	Caused by: org.apache.hadoop.metrics2.MetricsException: Metrics source LocalJobRunnerMetrics-1090927800
already exists!
		at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.newSourceName(DefaultMetricsSystem.java:152)
		at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.sourceName(DefaultMetricsSystem.java:125)
		at org.apache.hadoop.metrics2.impl.MetricsSystemImpl.register(MetricsSystemImpl.java:229)
		at org.apache.hadoop.mapred.LocalJobRunnerMetrics.create(LocalJobRunnerMetrics.java:46)
...
{code}

It seems that it tries to generate a unique metrics source name using a random 32-bit integer.
When running some longer-lived program that runs many separate jobs (such as HS2) this can
easily collide. https://en.wikipedia.org/wiki/Birthday_attack has some tables for the probabilities.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: mapreduce-dev-unsubscribe@hadoop.apache.org
For additional commands, e-mail: mapreduce-dev-help@hadoop.apache.org


Mime
View raw message