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HADOOP-8866. SampleQuantiles#query is O(N^2) instead of O(N). Contributed by Andrew Wang.

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git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1391711 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Aaron Myers 2012-09-29 00:59:04 +00:00
parent e8dc3b3a8a
commit 1ced82cc81
2 changed files with 8 additions and 2 deletions
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3
hadoop-common-project/hadoop-common/CHANGES.txt
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@ -280,6 +280,9 @@ Release 2.0.3-alpha - Unreleased
OPTIMIZATIONS
HADOOP-8866. SampleQuantiles#query is O(N^2) instead of O(N). (Andrew Wang
via atm)
BUG FIXES
HADOOP-8795. BASH tab completion doesn't look in PATH, assumes path to

7
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/util/SampleQuantiles.java
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@ -210,9 +210,12 @@ private long query(double quantile) throws IOException {
int rankMin = 0;
int desired = (int) (quantile * count);
ListIterator<SampleItem> it = samples.listIterator();
SampleItem prev = null;
SampleItem cur = it.next();
for (int i = 1; i < samples.size(); i++) {
SampleItem prev = samples.get(i - 1);
SampleItem cur = samples.get(i);
prev = cur;
cur = it.next();
rankMin += prev.g;