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Posted to commits@hbase.apache.org by st...@apache.org on 2014/10/02 19:39:04 UTC
git commit: HBASE-12133 Add FastLongHistogram for metric computation
(Yi Deng)
Repository: hbase
Updated Branches:
refs/heads/master e92036cd5 -> 0e1e64b82
HBASE-12133 Add FastLongHistogram for metric computation (Yi Deng)
Project: http://git-wip-us.apache.org/repos/asf/hbase/repo
Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/0e1e64b8
Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/0e1e64b8
Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/0e1e64b8
Branch: refs/heads/master
Commit: 0e1e64b821ad052e0f99ed40de12618f76c8465d
Parents: e92036c
Author: stack <st...@apache.org>
Authored: Thu Oct 2 10:38:56 2014 -0700
Committer: stack <st...@apache.org>
Committed: Thu Oct 2 10:38:56 2014 -0700
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.../apache/hadoop/hbase/util/AtomicUtils.java | 63 +++++
.../hadoop/hbase/util/FastLongHistogram.java | 233 +++++++++++++++++++
.../hbase/util/TestFastLongHistogram.java | 99 ++++++++
3 files changed, 395 insertions(+)
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http://git-wip-us.apache.org/repos/asf/hbase/blob/0e1e64b8/hbase-common/src/main/java/org/apache/hadoop/hbase/util/AtomicUtils.java
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diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/AtomicUtils.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/AtomicUtils.java
new file mode 100644
index 0000000..35391ee
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/AtomicUtils.java
@@ -0,0 +1,63 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.util;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+
+/**
+ * Utilities related to atomic operations.
+ */
+@InterfaceAudience.Private
+public class AtomicUtils {
+ /**
+ * Updates a AtomicLong which is supposed to maintain the minimum values. This method is not
+ * synchronized but is thread-safe.
+ */
+ public static void updateMin(AtomicLong min, long value) {
+ while (true) {
+ long cur = min.get();
+ if (value >= cur) {
+ break;
+ }
+
+ if (min.compareAndSet(cur, value)) {
+ break;
+ }
+ }
+ }
+
+ /**
+ * Updates a AtomicLong which is supposed to maintain the maximum values. This method is not
+ * synchronized but is thread-safe.
+ */
+ public static void updateMax(AtomicLong max, long value) {
+ while (true) {
+ long cur = max.get();
+ if (value <= cur) {
+ break;
+ }
+
+ if (max.compareAndSet(cur, value)) {
+ break;
+ }
+ }
+ }
+
+}
http://git-wip-us.apache.org/repos/asf/hbase/blob/0e1e64b8/hbase-common/src/main/java/org/apache/hadoop/hbase/util/FastLongHistogram.java
----------------------------------------------------------------------
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/FastLongHistogram.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/FastLongHistogram.java
new file mode 100644
index 0000000..623cbdb
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/FastLongHistogram.java
@@ -0,0 +1,233 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.util;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicLongArray;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.classification.InterfaceStability;
+
+/**
+ * FastLongHistogram is a thread-safe class that estimate distribution of data and computes the
+ * quantiles.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public class FastLongHistogram {
+ /**
+ * Bins is a class containing a list of buckets(or bins) for estimation histogram of some data.
+ */
+ private static class Bins {
+ private final AtomicLongArray counts;
+ // inclusive
+ private final long binsMin;
+ // exclusive
+ private final long binsMax;
+ private final long bins10XMax;
+ private final AtomicLong min = new AtomicLong(Long.MAX_VALUE);
+ private final AtomicLong max = new AtomicLong(0L);
+ // set to true when any of data has been inserted to the Bins. It is set after the counts are
+ // updated.
+ private final AtomicBoolean hasData = new AtomicBoolean(false);
+
+ /**
+ * The constructor for creating a Bins without any prior data.
+ */
+ public Bins() {
+ this.counts = new AtomicLongArray(4);
+ this.binsMin = 0L;
+ this.binsMax = Long.MAX_VALUE;
+ this.bins10XMax = Long.MAX_VALUE;
+ }
+
+ /**
+ * The constructor for creating a Bins with last Bins.
+ * @param last the last Bins instance.
+ * @param quantiles the quantiles for creating the bins of the histogram.
+ */
+ public Bins(Bins last, int numOfBins, double minQ, double maxQ) {
+ long[] values = last.getQuantiles(new double[] { minQ, maxQ });
+ long wd = values[1] - values[0] + 1;
+ // expand minQ and maxQ in two ends back assuming uniform distribution
+ this.binsMin = Math.max(0L, (long) (values[0] - wd * minQ));
+ long binsMax = (long) (values[1] + wd * (1 - maxQ)) + 1;
+ // make sure each of bins is at least of width 1
+ this.binsMax = Math.max(binsMax, this.binsMin + numOfBins);
+ this.bins10XMax = Math.max((long) (values[1] + (binsMax - 1) * 9), this.binsMax + 1);
+
+ this.counts = new AtomicLongArray(numOfBins + 3);
+ }
+
+ /**
+ * Adds a value to the histogram.
+ */
+ public void add(long value, long count) {
+ AtomicUtils.updateMin(min, value);
+ AtomicUtils.updateMax(max, value);
+
+ if (value < this.binsMin) {
+ this.counts.addAndGet(0, count);
+ } else if (value > this.bins10XMax) {
+ this.counts.addAndGet(this.counts.length() - 1, count);
+ } else if (value >= this.binsMax) {
+ this.counts.addAndGet(this.counts.length() - 2, count);
+ } else {
+ // compute the position
+ int pos =
+ 1 + (int) ((value - this.binsMin) * (this.counts.length() - 3) / (this.binsMax - this.binsMin));
+ this.counts.addAndGet(pos, count);
+ }
+
+ // hasData needs to be updated as last
+ this.hasData.set(true);
+ }
+
+ /**
+ * Computes the quantiles give the ratios.
+ * @param smooth set to true to have a prior on the distribution. Used for recreating the bins.
+ */
+ public long[] getQuantiles(double[] quantiles) {
+ if (!this.hasData.get()) {
+ // No data yet.
+ return new long[quantiles.length];
+ }
+
+ // Make a snapshot of lowerCounter, higherCounter and bins.counts to counts.
+ // This is not synchronized, but since the counter are accumulating, the result is a good
+ // estimation of a snapshot.
+ long[] counts = new long[this.counts.length()];
+ long total = 0L;
+ for (int i = 0; i < this.counts.length(); i++) {
+ counts[i] = this.counts.get(i);
+ total += counts[i];
+ }
+
+ int rIndex = 0;
+ double qCount = total * quantiles[0];
+ long cum = 0L;
+
+ long[] res = new long[quantiles.length];
+ countsLoop: for (int i = 0; i < counts.length; i++) {
+ // mn and mx define a value range
+ long mn, mx;
+ if (i == 0) {
+ mn = this.min.get();
+ mx = this.binsMin;
+ } else if (i == counts.length - 1) {
+ mn = this.bins10XMax;
+ mx = this.max.get();
+ } else if (i == counts.length - 2) {
+ mn = this.binsMax;
+ mx = this.bins10XMax;
+ } else {
+ mn = this.binsMin + (i - 1) * (this.binsMax - this.binsMin) / (this.counts.length() - 3);
+ mx = this.binsMin + i * (this.binsMax - this.binsMin) / (this.counts.length() - 3);
+ }
+
+ if (mx < this.min.get()) {
+ continue;
+ }
+ if (mn > this.max.get()) {
+ break;
+ }
+ mn = Math.max(mn, this.min.get());
+ mx = Math.min(mx, this.max.get());
+
+ // lastCum/cum are the corresponding counts to mn/mx
+ double lastCum = cum;
+ cum += counts[i];
+
+ // fill the results for qCount is within current range.
+ while (qCount <= cum) {
+ if (cum == lastCum) {
+ res[rIndex] = mn;
+ } else {
+ res[rIndex] = (long) ((qCount - lastCum) * (mx - mn) / (cum - lastCum) + mn);
+ }
+
+ // move to next quantile
+ rIndex++;
+ if (rIndex >= quantiles.length) {
+ break countsLoop;
+ }
+ qCount = total * quantiles[rIndex];
+ }
+ }
+ // In case quantiles contains values >= 100%
+ for (; rIndex < quantiles.length; rIndex++) {
+ res[rIndex] = this.max.get();
+ }
+
+ return res;
+ }
+ }
+
+ // The bins counting values. It is replaced with a new one in calling of reset().
+ private volatile Bins bins = new Bins();
+ // The quantiles for creating a Bins with last Bins.
+ private final int numOfBins;
+
+ /**
+ * Constructor.
+ * @param numOfBins the number of bins for the histogram. A larger value results in more precise
+ * results but with lower efficiency, and vice versus.
+ */
+ public FastLongHistogram(int numOfBins) {
+ this.numOfBins = numOfBins;
+ }
+
+ /**
+ * Constructor setting the bins assuming a uniform distribution within a range.
+ * @param numOfBins the number of bins for the histogram. A larger value results in more precise
+ * results but with lower efficiency, and vice versus.
+ * @param min lower bound of the region, inclusive.
+ * @param max higher bound of the region, inclusive.
+ */
+ public FastLongHistogram(int numOfBins, long min, long max) {
+ this(numOfBins);
+ Bins bins = new Bins();
+ bins.add(min, 1);
+ bins.add(max, 1);
+ this.bins = new Bins(bins, numOfBins, 0.01, 0.99);
+ }
+
+ /**
+ * Adds a value to the histogram.
+ */
+ public void add(long value, long count) {
+ this.bins.add(value, count);
+ }
+
+ /**
+ * Computes the quantiles give the ratios.
+ */
+ public long[] getQuantiles(double[] quantiles) {
+ return this.bins.getQuantiles(quantiles);
+ }
+
+ /**
+ * Resets the histogram for new counting.
+ */
+ public void reset() {
+ if (this.bins.hasData.get()) {
+ this.bins = new Bins(this.bins, numOfBins, 0.01, 0.99);
+ }
+ }
+}
http://git-wip-us.apache.org/repos/asf/hbase/blob/0e1e64b8/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestFastLongHistogram.java
----------------------------------------------------------------------
diff --git a/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestFastLongHistogram.java b/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestFastLongHistogram.java
new file mode 100644
index 0000000..e0437b5
--- /dev/null
+++ b/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestFastLongHistogram.java
@@ -0,0 +1,99 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.util;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.apache.hadoop.hbase.SmallTests;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+/**
+ * Testcases for FastLongHistogram.
+ */
+@Category({ SmallTests.class })
+public class TestFastLongHistogram {
+
+ private static void doTestUniform(FastLongHistogram hist) {
+ long[] VALUES = { 0, 10, 20, 30, 40, 50 };
+ double[] qs = new double[VALUES.length];
+ for (int i = 0; i < qs.length; i++) {
+ qs[i] = (double) VALUES[i] / VALUES[VALUES.length - 1];
+ }
+
+ for (int i = 0; i < 10; i++) {
+ for (long v : VALUES) {
+ hist.add(v, 1);
+ }
+ long[] vals = hist.getQuantiles(qs);
+ System.out.println(Arrays.toString(vals));
+ for (int j = 0; j < qs.length; j++) {
+ Assert.assertTrue(j + "-th element org: " + VALUES[j] + ", act: " + vals[j],
+ Math.abs(vals[j] - VALUES[j]) <= 10);
+ }
+ hist.reset();
+ }
+ }
+
+ @Test
+ public void testUniform() {
+ FastLongHistogram hist = new FastLongHistogram(100, 0, 50);
+ doTestUniform(hist);
+ }
+
+ @Test
+ public void testAdaptionOfChange() {
+ // assumes the uniform distribution
+ FastLongHistogram hist = new FastLongHistogram(100, 0, 100);
+
+ Random rand = new Random();
+
+ for (int n = 0; n < 10; n++) {
+ for (int i = 0; i < 900; i++) {
+ hist.add(rand.nextInt(100), 1);
+ }
+
+ // add 10% outliers, this breaks the assumption, hope bin10xMax works
+ for (int i = 0; i < 100; i++) {
+ hist.add(1000 + rand.nextInt(100), 1);
+ }
+
+ long[] vals = hist.getQuantiles(new double[] { 0.25, 0.75, 0.95 });
+ System.out.println(Arrays.toString(vals));
+ if (n == 0) {
+ Assert.assertTrue("Out of possible value", vals[0] >= 0 && vals[0] <= 50);
+ Assert.assertTrue("Out of possible value", vals[1] >= 50 && vals[1] <= 100);
+ Assert.assertTrue("Out of possible value", vals[2] >= 900 && vals[2] <= 1100);
+ }
+
+ hist.reset();
+ }
+ }
+
+ @Test
+ public void testSameValues() {
+ FastLongHistogram hist = new FastLongHistogram(100);
+
+ hist.add(50, 100);
+
+ hist.reset();
+ doTestUniform(hist);
+ }
+}