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-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: mapreduce-issues-h...@hadoop.apache.org