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https://issues.apache.org/jira/browse/MAPREDUCE-5288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13674641#comment-13674641
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Karthik Kambatla commented on MAPREDUCE-5288:
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[~qwertymaniac], is it a problem if the estimate is Long.MAX_VALUE? To frame it
differently, if no maps completed (may be due to the infinite amount of work
each map does), what other value would we set this to.
[~azuryy], I am not sure if the snippet posted addresses the issue Harsh
reported.
> ResourceEstimator#getEstimatedTotalMapOutputSize suffers from divide by zero
> issues
> -----------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5288
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5288
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv1
> Affects Versions: 1.2.0
> Reporter: Harsh J
> Assignee: Karthik Kambatla
>
> The computation in the above mentioned class-method is below:
> {code}
> long estimate = Math.round(((double)inputSize *
> completedMapsOutputSize * 2.0)/completedMapsInputSize);
> {code}
> Given
> http://docs.oracle.com/javase/6/docs/api/java/lang/Math.html#round(double),
> its possible that the returned estimate could be Long.MAX_VALUE if
> completedMapsInputSize is determined to be zero.
> This can be proven with a simple code snippet:
> {code}
> class Foo {
> public static void main(String... args) {
> long inputSize = 600L + 2;
> long estimate = Math.round(((double)inputSize *
> 1L * 2.0)/0L);
> System.out.println(estimate);
> }
> }
> {code}
> The above conveniently prints out: {{9223372036854775807}}, which is
> Long.MAX_VALUE (or 8 Exbibytes per MapReduce).
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