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HADOOP-8052. Hadoop Metrics2 should emit Float.MAX_VALUE (instead of Double.MAX_VALUE) to avoid making Ganglia's gmetad core. Contributed by Varun Kapoor. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1243206 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Matthew Foley 2012-02-12 07:31:12 +00:00
parent 3b37072e59
commit 04a8e11de7
3 changed files with 21 additions and 9 deletions
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6
hadoop-common-project/hadoop-common/CHANGES.txt
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@ -26,7 +26,11 @@ Release 0.23.2 - UNRELEASED
HADOOP-8051 HttpFS documentation it is not wired to the generated site (tucu)
HADOOP-8055. Hadoop tarball distribution lacks a core-site.xml (harsh)
HADOOP-8055. Hadoop tarball distribution lacks a core-site.xml (harsh)
HADOOP-8052. Hadoop Metrics2 should emit Float.MAX_VALUE (instead of
Double.MAX_VALUE) to avoid making Ganglia's gmetad core. (Varun Kapoor
via mattf)
Release 0.23.1 - 2012-02-08

16
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/util/SampleStat.java
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@ -143,8 +143,16 @@ public class SampleStat {
@SuppressWarnings("PublicInnerClass")
public static class MinMax {
private double min = Double.MAX_VALUE;
private double max = Double.MIN_VALUE;
// Float.MAX_VALUE is used rather than Double.MAX_VALUE, even though the
// min and max variables are of type double.
// Float.MAX_VALUE is big enough, and using Double.MAX_VALUE makes
// Ganglia core due to buffer overflow.
// The same reasoning applies to the MIN_VALUE counterparts.
static final double DEFAULT_MIN_VALUE = Float.MAX_VALUE;
static final double DEFAULT_MAX_VALUE = Float.MIN_VALUE;
private double min = DEFAULT_MIN_VALUE;
private double max = DEFAULT_MAX_VALUE;
public void add(double value) {
if (value > max) max = value;
@ -155,8 +163,8 @@ public class SampleStat {
public double max() { return max; }
public void reset() {
min = Double.MAX_VALUE;
max = Double.MIN_VALUE;
min = DEFAULT_MIN_VALUE;
max = DEFAULT_MAX_VALUE;
}
public void reset(MinMax other) {

8
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/util/TestSampleStat.java
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@ -36,8 +36,8 @@ public class TestSampleStat {
assertEquals("mean", 0.0, stat.mean(), EPSILON);
assertEquals("variance", 0.0, stat.variance(), EPSILON);
assertEquals("stddev", 0.0, stat.stddev(), EPSILON);
assertEquals("min", Double.MAX_VALUE, stat.min(), EPSILON);
assertEquals("max", Double.MIN_VALUE, stat.max(), EPSILON);
assertEquals("min", SampleStat.MinMax.DEFAULT_MIN_VALUE, stat.min(), EPSILON);
assertEquals("max", SampleStat.MinMax.DEFAULT_MAX_VALUE, stat.max(), EPSILON);
stat.add(3);
assertEquals("num samples", 1L, stat.numSamples());
@ -60,8 +60,8 @@ public class TestSampleStat {
assertEquals("mean", 0.0, stat.mean(), EPSILON);
assertEquals("variance", 0.0, stat.variance(), EPSILON);
assertEquals("stddev", 0.0, stat.stddev(), EPSILON);
assertEquals("min", Double.MAX_VALUE, stat.min(), EPSILON);
assertEquals("max", Double.MIN_VALUE, stat.max(), EPSILON);
assertEquals("min", SampleStat.MinMax.DEFAULT_MIN_VALUE, stat.min(), EPSILON);
assertEquals("max", SampleStat.MinMax.DEFAULT_MAX_VALUE, stat.max(), EPSILON);
}
}