Anubhav Dhoot created MAPREDUCE-5979:
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Summary: MR1 FairScheduler zero weight can cause sort failures
Key: MAPREDUCE-5979
URL: https://issues.apache.org/jira/browse/MAPREDUCE-5979
Project: Hadoop Map/Reduce
Issue Type: Bug
Components: scheduler
Affects Versions: 1.2.1
Reporter: Anubhav Dhoot
When the weight is set to zero (which is possible with a custom weight
adjuster) we can get failures in comparing schedulables.
This is because when calculating running tasks to weight ratio could result in
a 0.0/0.0 which ends up as NaN. Comparisons with NaN are undefined such that
(int)Math.signum(NaN - anyNumber) will be 0 causing different criteria to be
used in comparison which may not be consistent. This will result in
{{IllegalArgumentException: Comparison method violates its general contract!}}
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