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https://issues.apache.org/jira/browse/HADOOP-3442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603949#action_12603949
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szetszwo edited comment on HADOOP-3442 at 6/10/08 10:53 AM:
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> Even with all these fixes, I still believe it is good to add randomization to
> pivotal selection (or randomize the input data upfront).
I also like randomized quick sort. However, we better fix the stack overflow
problem first. Then, we could think about how to improve the sorting algorithm.
> The 2*log\(n) heuristic was intended to bail out of a worst case, not to
> protect against the StackOverflowError
I think the 2*log n heuristic not only bail out of worst cases but also good
cases since it is overly strict.
I agree that we should force on fixing the problem in this issue. 3442-3.patch
is already very good. +1
was (Author: szetszwo):
> Even with all these fixes, I still believe it is good to add
randomization to pivotal selection (or randomize the input data upfront).
I also like randomized quick sort. However, we better fix the stack overflow
problem first. Then, we could think about how to improve the sorting algorithm.
> The 2*log(n) heuristic was intended to bail out of a worst case, not to
> protect against the StackOverflowError
I think the 2*log(n) heuristic not only bail out of worst cases but also good
cases since it is overly strict.
I agree that we should force on fixing the problem in this issue. 3442-3.patch
is already very good. +1
> QuickSort may get into unbounded recursion
> ------------------------------------------
>
> Key: HADOOP-3442
> URL: https://issues.apache.org/jira/browse/HADOOP-3442
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.17.0
> Reporter: Runping Qi
> Assignee: Chris Douglas
> Priority: Blocker
> Fix For: 0.17.1, 0.18.0
>
> Attachments: 3442-0.patch, 3442-0v17.patch, 3442-1.patch,
> 3442-2.patch, 3442-3.patch, CheckSortBuffer.java, HADOOP-3442.patch,
> overflow.zip, spillbuffers.patch
>
>
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