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Posted to commits@hbase.apache.org by ap...@apache.org on 2022/01/28 00:48:51 UTC
[hbase] branch branch-2.5 updated: HBASE-26719 Remove 'patch' file added as part of commit for HBASE-25973
This is an automated email from the ASF dual-hosted git repository.
apurtell pushed a commit to branch branch-2.5
in repository https://gitbox.apache.org/repos/asf/hbase.git
The following commit(s) were added to refs/heads/branch-2.5 by this push:
new 86e51da HBASE-26719 Remove 'patch' file added as part of commit for HBASE-25973
86e51da is described below
commit 86e51da2b8b76bbd2cf391cce146d12a8b77b069
Author: Andrew Purtell <ap...@apache.org>
AuthorDate: Thu Jan 27 16:47:14 2022 -0800
HBASE-26719 Remove 'patch' file added as part of commit for HBASE-25973
Signed-off-by: Andrew Purtell <ap...@apache.org>
---
patch | 838 ------------------------------------------------------------------
1 file changed, 838 deletions(-)
diff --git a/patch b/patch
deleted file mode 100644
index f084524..0000000
--- a/patch
+++ /dev/null
@@ -1,838 +0,0 @@
-From debf8555c2fb0f309e3389aa196a788d8c4a5bb5 Mon Sep 17 00:00:00 2001
-From: Duo Zhang <zh...@apache.org>
-Date: Sat, 29 May 2021 10:54:44 +0800
-Subject: [PATCH] HBASE-25947 Backport 'HBASE-25894 Improve the performance for
- region load and region count related cost functions' to branch-2.4 and
- branch-2.3
-
----
- .../master/balancer/DoubleArrayCost.java | 100 ++++++
- .../balancer/StochasticLoadBalancer.java | 337 +++++++++---------
- .../master/balancer/TestDoubleArrayCost.java | 67 ++++
- .../TestStochasticBalancerJmxMetrics.java | 19 +-
- .../balancer/TestStochasticLoadBalancer.java | 28 --
- 5 files changed, 342 insertions(+), 209 deletions(-)
- create mode 100644 hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/DoubleArrayCost.java
- create mode 100644 hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestDoubleArrayCost.java
- rename hbase-server/src/test/java/org/apache/hadoop/hbase/{ => master/balancer}/TestStochasticBalancerJmxMetrics.java (95%)
-
-diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/DoubleArrayCost.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/DoubleArrayCost.java
-new file mode 100644
-index 000000000000..f370b8077d1b
---- /dev/null
-+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/DoubleArrayCost.java
-@@ -0,0 +1,100 @@
-+/**
-+ * 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.master.balancer;
-+
-+import java.util.function.Consumer;
-+import org.apache.yetus.audience.InterfaceAudience;
-+
-+/**
-+ * A helper class to compute a scaled cost using
-+ * {@link org.apache.commons.math3.stat.descriptive.DescriptiveStatistics#DescriptiveStatistics()}.
-+ * It assumes that this is a zero sum set of costs. It assumes that the worst case possible is all
-+ * of the elements in one region server and the rest having 0.
-+ */
-+@InterfaceAudience.Private
-+final class DoubleArrayCost {
-+
-+ private double[] costs;
-+
-+ // computeCost call is expensive so we use this flag to indicate whether we need to recalculate
-+ // the cost by calling computeCost
-+ private boolean costsChanged;
-+
-+ private double cost;
-+
-+ void prepare(int length) {
-+ if (costs == null || costs.length != length) {
-+ costs = new double[length];
-+ }
-+ }
-+
-+ void setCosts(Consumer<double[]> consumer) {
-+ consumer.accept(costs);
-+ costsChanged = true;
-+ }
-+
-+ double cost() {
-+ if (costsChanged) {
-+ cost = computeCost(costs);
-+ costsChanged = false;
-+ }
-+ return cost;
-+ }
-+
-+ private static double computeCost(double[] stats) {
-+ double totalCost = 0;
-+ double total = getSum(stats);
-+
-+ double count = stats.length;
-+ double mean = total / count;
-+
-+ // Compute max as if all region servers had 0 and one had the sum of all costs. This must be
-+ // a zero sum cost for this to make sense.
-+ double max = ((count - 1) * mean) + (total - mean);
-+
-+ // It's possible that there aren't enough regions to go around
-+ double min;
-+ if (count > total) {
-+ min = ((count - total) * mean) + ((1 - mean) * total);
-+ } else {
-+ // Some will have 1 more than everything else.
-+ int numHigh = (int) (total - (Math.floor(mean) * count));
-+ int numLow = (int) (count - numHigh);
-+
-+ min = (numHigh * (Math.ceil(mean) - mean)) + (numLow * (mean - Math.floor(mean)));
-+
-+ }
-+ min = Math.max(0, min);
-+ for (int i = 0; i < stats.length; i++) {
-+ double n = stats[i];
-+ double diff = Math.abs(mean - n);
-+ totalCost += diff;
-+ }
-+
-+ double scaled = StochasticLoadBalancer.scale(min, max, totalCost);
-+ return scaled;
-+ }
-+
-+ private static double getSum(double[] stats) {
-+ double total = 0;
-+ for (double s : stats) {
-+ total += s;
-+ }
-+ return total;
-+ }
-+}
-\ No newline at end of file
-diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
-index 3e341d0f7718..26d8d43f5bef 100644
---- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
-+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
-@@ -17,12 +17,14 @@
- */
- package org.apache.hadoop.hbase.master.balancer;
-
-+import com.google.errorprone.annotations.RestrictedApi;
- import java.util.ArrayDeque;
- import java.util.ArrayList;
- import java.util.Arrays;
- import java.util.Collection;
- import java.util.Deque;
- import java.util.HashMap;
-+import java.util.Iterator;
- import java.util.LinkedList;
- import java.util.List;
- import java.util.Map;
-@@ -145,7 +147,6 @@
- private boolean isBalancerRejectionRecording = false;
-
- private List<CandidateGenerator> candidateGenerators;
-- private CostFromRegionLoadFunction[] regionLoadFunctions;
- private List<CostFunction> costFunctions; // FindBugs: Wants this protected; IS2_INCONSISTENT_SYNC
-
- // to save and report costs to JMX
-@@ -202,12 +203,6 @@ public synchronized void setConf(Configuration conf) {
- candidateGenerators.add(localityCandidateGenerator);
- candidateGenerators.add(new RegionReplicaRackCandidateGenerator());
- }
-- regionLoadFunctions = new CostFromRegionLoadFunction[] {
-- new ReadRequestCostFunction(conf),
-- new WriteRequestCostFunction(conf),
-- new MemStoreSizeCostFunction(conf),
-- new StoreFileCostFunction(conf)
-- };
- regionReplicaHostCostFunction = new RegionReplicaHostCostFunction(conf);
- regionReplicaRackCostFunction = new RegionReplicaRackCostFunction(conf);
-
-@@ -220,10 +215,10 @@ public synchronized void setConf(Configuration conf) {
- addCostFunction(new TableSkewCostFunction(conf));
- addCostFunction(regionReplicaHostCostFunction);
- addCostFunction(regionReplicaRackCostFunction);
-- addCostFunction(regionLoadFunctions[0]);
-- addCostFunction(regionLoadFunctions[1]);
-- addCostFunction(regionLoadFunctions[2]);
-- addCostFunction(regionLoadFunctions[3]);
-+ addCostFunction(new ReadRequestCostFunction(conf));
-+ addCostFunction(new WriteRequestCostFunction(conf));
-+ addCostFunction(new MemStoreSizeCostFunction(conf));
-+ addCostFunction(new StoreFileCostFunction(conf));
- loadCustomCostFunctions(conf);
-
- curFunctionCosts = new double[costFunctions.size()];
-@@ -290,9 +285,6 @@ protected void setSlop(Configuration conf) {
- public synchronized void setClusterMetrics(ClusterMetrics st) {
- super.setClusterMetrics(st);
- updateRegionLoad();
-- for(CostFromRegionLoadFunction cost : regionLoadFunctions) {
-- cost.setClusterMetrics(st);
-- }
-
- // update metrics size
- try {
-@@ -599,12 +591,16 @@ private void addCostFunction(CostFunction costFunction) {
-
- private String functionCost() {
- StringBuilder builder = new StringBuilder();
-- for (CostFunction c:costFunctions) {
-+ for (CostFunction c : costFunctions) {
- builder.append(c.getClass().getSimpleName());
- builder.append(" : (");
-- builder.append(c.getMultiplier());
-- builder.append(", ");
-- builder.append(c.cost());
-+ if (c.isNeeded()) {
-+ builder.append(c.getMultiplier());
-+ builder.append(", ");
-+ builder.append(c.cost());
-+ } else {
-+ builder.append("not needed");
-+ }
- builder.append("); ");
- }
- return builder.toString();
-@@ -613,11 +609,15 @@ private String functionCost() {
- private String totalCostsPerFunc() {
- StringBuilder builder = new StringBuilder();
- for (CostFunction c : costFunctions) {
-- if (c.getMultiplier() * c.cost() > 0.0) {
-+ if (c.getMultiplier() <= 0 || !c.isNeeded()) {
-+ continue;
-+ }
-+ double cost = c.getMultiplier() * c.cost();
-+ if (cost > 0.0) {
- builder.append(" ");
- builder.append(c.getClass().getSimpleName());
- builder.append(" : ");
-- builder.append(c.getMultiplier() * c.cost());
-+ builder.append(cost);
- builder.append(";");
- }
- }
-@@ -679,29 +679,32 @@ private synchronized void updateRegionLoad() {
- loads.put(regionNameAsString, rLoads);
- });
- });
--
-- for(CostFromRegionLoadFunction cost : regionLoadFunctions) {
-- cost.setLoads(loads);
-- }
- }
-
-- protected void initCosts(Cluster cluster) {
-+ @RestrictedApi(explanation = "Should only be called in tests", link = "",
-+ allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java")
-+ void initCosts(Cluster cluster) {
- for (CostFunction c:costFunctions) {
- c.init(cluster);
- }
- }
-
-- protected void updateCostsWithAction(Cluster cluster, Action action) {
-+ @RestrictedApi(explanation = "Should only be called in tests", link = "",
-+ allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java")
-+ void updateCostsWithAction(Cluster cluster, Action action) {
- for (CostFunction c : costFunctions) {
-- c.postAction(action);
-+ if (c.getMultiplier() > 0 && c.isNeeded()) {
-+ c.postAction(action);
-+ }
- }
- }
-
- /**
- * Get the names of the cost functions
- */
-- public String[] getCostFunctionNames() {
-- if (costFunctions == null) return null;
-+ @RestrictedApi(explanation = "Should only be called in tests", link = "",
-+ allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java")
-+ String[] getCostFunctionNames() {
- String[] ret = new String[costFunctions.size()];
- for (int i = 0; i < costFunctions.size(); i++) {
- CostFunction c = costFunctions.get(i);
-@@ -720,14 +723,16 @@ protected void updateCostsWithAction(Cluster cluster, Action action) {
- * @return a double of a cost associated with the proposed cluster state. This cost is an
- * aggregate of all individual cost functions.
- */
-- protected double computeCost(Cluster cluster, double previousCost) {
-+ @RestrictedApi(explanation = "Should only be called in tests", link = "",
-+ allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java")
-+ double computeCost(Cluster cluster, double previousCost) {
- double total = 0;
-
- for (int i = 0; i < costFunctions.size(); i++) {
- CostFunction c = costFunctions.get(i);
- this.tempFunctionCosts[i] = 0.0;
-
-- if (c.getMultiplier() <= 0) {
-+ if (c.getMultiplier() <= 0 || !c.isNeeded()) {
- continue;
- }
-
-@@ -851,75 +856,24 @@ protected void regionMoved(int region, int oldServer, int newServer) {
- }
-
- protected abstract double cost();
-+ }
-
-- @SuppressWarnings("checkstyle:linelength")
-- /**
-- * Function to compute a scaled cost using
-- * {@link org.apache.commons.math3.stat.descriptive.DescriptiveStatistics#DescriptiveStatistics()}.
-- * It assumes that this is a zero sum set of costs. It assumes that the worst case
-- * possible is all of the elements in one region server and the rest having 0.
-- *
-- * @param stats the costs
-- * @return a scaled set of costs.
-- */
-- protected double costFromArray(double[] stats) {
-- double totalCost = 0;
-- double total = getSum(stats);
--
-- double count = stats.length;
-- double mean = total/count;
--
-- // Compute max as if all region servers had 0 and one had the sum of all costs. This must be
-- // a zero sum cost for this to make sense.
-- double max = ((count - 1) * mean) + (total - mean);
--
-- // It's possible that there aren't enough regions to go around
-- double min;
-- if (count > total) {
-- min = ((count - total) * mean) + ((1 - mean) * total);
-- } else {
-- // Some will have 1 more than everything else.
-- int numHigh = (int) (total - (Math.floor(mean) * count));
-- int numLow = (int) (count - numHigh);
--
-- min = (numHigh * (Math.ceil(mean) - mean)) + (numLow * (mean - Math.floor(mean)));
--
-- }
-- min = Math.max(0, min);
-- for (int i=0; i<stats.length; i++) {
-- double n = stats[i];
-- double diff = Math.abs(mean - n);
-- totalCost += diff;
-- }
--
-- double scaled = scale(min, max, totalCost);
-- return scaled;
-+ /**
-+ * Scale the value between 0 and 1.
-+ * @param min Min value
-+ * @param max The Max value
-+ * @param value The value to be scaled.
-+ * @return The scaled value.
-+ */
-+ static double scale(double min, double max, double value) {
-+ if (max <= min || value <= min) {
-+ return 0;
- }
--
-- private double getSum(double[] stats) {
-- double total = 0;
-- for(double s:stats) {
-- total += s;
-- }
-- return total;
-+ if ((max - min) == 0) {
-+ return 0;
- }
-
-- /**
-- * Scale the value between 0 and 1.
-- *
-- * @param min Min value
-- * @param max The Max value
-- * @param value The value to be scaled.
-- * @return The scaled value.
-- */
-- protected double scale(double min, double max, double value) {
-- if (max <= min || value <= min) {
-- return 0;
-- }
-- if ((max - min) == 0) return 0;
--
-- return Math.max(0d, Math.min(1d, (value - min) / (max - min)));
-- }
-+ return Math.max(0d, Math.min(1d, (value - min) / (max - min)));
- }
-
- /**
-@@ -938,28 +892,36 @@ protected double scale(double min, double max, double value) {
- private static final float DEFAULT_MAX_MOVE_PERCENT = 0.25f;
-
- private final float maxMovesPercent;
-- private final Configuration conf;
-+ private final OffPeakHours offPeakHours;
-+ private final float moveCost;
-+ private final float moveCostOffPeak;
-
- MoveCostFunction(Configuration conf) {
- super(conf);
-- this.conf = conf;
- // What percent of the number of regions a single run of the balancer can move.
- maxMovesPercent = conf.getFloat(MAX_MOVES_PERCENT_KEY, DEFAULT_MAX_MOVE_PERCENT);
--
-+ offPeakHours = OffPeakHours.getInstance(conf);
-+ moveCost = conf.getFloat(MOVE_COST_KEY, DEFAULT_MOVE_COST);
-+ moveCostOffPeak = conf.getFloat(MOVE_COST_OFFPEAK_KEY, DEFAULT_MOVE_COST_OFFPEAK);
- // Initialize the multiplier so that addCostFunction will add this cost function.
- // It may change during later evaluations, due to OffPeakHours.
-- this.setMultiplier(conf.getFloat(MOVE_COST_KEY, DEFAULT_MOVE_COST));
-+ this.setMultiplier(moveCost);
- }
-
- @Override
-- protected double cost() {
-+ void init(Cluster cluster) {
-+ super.init(cluster);
- // Move cost multiplier should be the same cost or higher than the rest of the costs to ensure
- // that large benefits are need to overcome the cost of a move.
-- if (OffPeakHours.getInstance(conf).isOffPeakHour()) {
-- this.setMultiplier(conf.getFloat(MOVE_COST_OFFPEAK_KEY, DEFAULT_MOVE_COST_OFFPEAK));
-+ if (offPeakHours.isOffPeakHour()) {
-+ this.setMultiplier(moveCostOffPeak);
- } else {
-- this.setMultiplier(conf.getFloat(MOVE_COST_KEY, DEFAULT_MOVE_COST));
-+ this.setMultiplier(moveCost);
- }
-+ }
-+
-+ @Override
-+ protected double cost() {
- // Try and size the max number of Moves, but always be prepared to move some.
- int maxMoves = Math.max((int) (cluster.numRegions * maxMovesPercent),
- DEFAULT_MAX_MOVES);
-@@ -985,7 +947,7 @@ protected double cost() {
- "hbase.master.balancer.stochastic.regionCountCost";
- static final float DEFAULT_REGION_COUNT_SKEW_COST = 500;
-
-- private double[] stats = null;
-+ private final DoubleArrayCost cost = new DoubleArrayCost();
-
- RegionCountSkewCostFunction(Configuration conf) {
- super(conf);
-@@ -996,8 +958,14 @@ protected double cost() {
- @Override
- void init(Cluster cluster) {
- super.init(cluster);
-+ cost.prepare(cluster.numServers);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < cluster.numServers; i++) {
-+ costs[i] = cluster.regionsPerServer[i].length;
-+ }
-+ });
- LOG.debug("{} sees a total of {} servers and {} regions.", getClass().getSimpleName(),
-- cluster.numServers, cluster.numRegions);
-+ cluster.numServers, cluster.numRegions);
- if (LOG.isTraceEnabled()) {
- for (int i =0; i < cluster.numServers; i++) {
- LOG.trace("{} sees server '{}' has {} regions", getClass().getSimpleName(),
-@@ -1008,13 +976,15 @@ void init(Cluster cluster) {
-
- @Override
- protected double cost() {
-- if (stats == null || stats.length != cluster.numServers) {
-- stats = new double[cluster.numServers];
-- }
-- for (int i =0; i < cluster.numServers; i++) {
-- stats[i] = cluster.regionsPerServer[i].length;
-- }
-- return costFromArray(stats);
-+ return cost.cost();
-+ }
-+
-+ @Override
-+ protected void regionMoved(int region, int oldServer, int newServer) {
-+ cost.setCosts(costs -> {
-+ costs[oldServer] = cluster.regionsPerServer[oldServer].length;
-+ costs[newServer] = cluster.regionsPerServer[newServer].length;
-+ });
- }
- }
-
-@@ -1027,7 +997,7 @@ protected double cost() {
- "hbase.master.balancer.stochastic.primaryRegionCountCost";
- private static final float DEFAULT_PRIMARY_REGION_COUNT_SKEW_COST = 500;
-
-- private double[] stats = null;
-+ private final DoubleArrayCost cost = new DoubleArrayCost();
-
- PrimaryRegionCountSkewCostFunction(Configuration conf) {
- super(conf);
-@@ -1036,30 +1006,45 @@ protected double cost() {
- DEFAULT_PRIMARY_REGION_COUNT_SKEW_COST));
- }
-
-+ private double computeCostForRegionServer(int regionServerIndex) {
-+ int cost = 0;
-+ for (int regionIdx : cluster.regionsPerServer[regionServerIndex]) {
-+ if (regionIdx == cluster.regionIndexToPrimaryIndex[regionIdx]) {
-+ cost++;
-+ }
-+ }
-+ return cost;
-+ }
-+
-+ @Override
-+ void init(Cluster cluster) {
-+ super.init(cluster);
-+ if (!isNeeded()) {
-+ return;
-+ }
-+ cost.prepare(cluster.numServers);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < costs.length; i++) {
-+ costs[i] = computeCostForRegionServer(i);
-+ }
-+ });
-+ }
-+
- @Override
- boolean isNeeded() {
- return cluster.hasRegionReplicas;
- }
-
-+ @Override
-+ protected void regionMoved(int region, int oldServer, int newServer) {
-+ cost.setCosts(costs -> {
-+ costs[oldServer] = computeCostForRegionServer(oldServer);
-+ costs[newServer] = computeCostForRegionServer(newServer);
-+ });
-+ }
- @Override
- protected double cost() {
-- if (!cluster.hasRegionReplicas) {
-- return 0;
-- }
-- if (stats == null || stats.length != cluster.numServers) {
-- stats = new double[cluster.numServers];
-- }
--
-- for (int i = 0; i < cluster.numServers; i++) {
-- stats[i] = 0;
-- for (int regionIdx : cluster.regionsPerServer[i]) {
-- if (regionIdx == cluster.regionIndexToPrimaryIndex[regionIdx]) {
-- stats[i]++;
-- }
-- }
-- }
--
-- return costFromArray(stats);
-+ return cost.cost();
- }
- }
-
-@@ -1194,51 +1179,51 @@ int regionIndexToEntityIndex(int region) {
- */
- abstract static class CostFromRegionLoadFunction extends CostFunction {
-
-- private ClusterMetrics clusterStatus = null;
-- private Map<String, Deque<BalancerRegionLoad>> loads = null;
-- private double[] stats = null;
-+ private final DoubleArrayCost cost = new DoubleArrayCost();
-+
- CostFromRegionLoadFunction(Configuration conf) {
- super(conf);
- }
-
-- void setClusterMetrics(ClusterMetrics status) {
-- this.clusterStatus = status;
-- }
--
-- void setLoads(Map<String, Deque<BalancerRegionLoad>> l) {
-- this.loads = l;
-- }
-+ private double computeCostForRegionServer(int regionServerIndex) {
-+ // Cost this server has from RegionLoad
-+ double cost = 0;
-
-- @Override
-- protected double cost() {
-- if (clusterStatus == null || loads == null) {
-- return 0;
-- }
-+ // for every region on this server get the rl
-+ for (int regionIndex : cluster.regionsPerServer[regionServerIndex]) {
-+ Collection<BalancerRegionLoad> regionLoadList = cluster.regionLoads[regionIndex];
-
-- if (stats == null || stats.length != cluster.numServers) {
-- stats = new double[cluster.numServers];
-+ // Now if we found a region load get the type of cost that was requested.
-+ if (regionLoadList != null) {
-+ cost += getRegionLoadCost(regionLoadList);
-+ }
- }
-+ return cost;
-+ }
-
-- for (int i =0; i < stats.length; i++) {
-- //Cost this server has from RegionLoad
-- long cost = 0;
--
-- // for every region on this server get the rl
-- for(int regionIndex:cluster.regionsPerServer[i]) {
-- Collection<BalancerRegionLoad> regionLoadList = cluster.regionLoads[regionIndex];
--
-- // Now if we found a region load get the type of cost that was requested.
-- if (regionLoadList != null) {
-- cost = (long) (cost + getRegionLoadCost(regionLoadList));
-- }
-+ @Override
-+ void init(Cluster cluster) {
-+ super.init(cluster);
-+ cost.prepare(cluster.numServers);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < costs.length; i++) {
-+ costs[i] = computeCostForRegionServer(i);
- }
-+ });
-+ }
-
-- // Add the total cost to the stats.
-- stats[i] = cost;
-- }
-+ @Override
-+ protected void regionMoved(int region, int oldServer, int newServer) {
-+ // recompute the stat for the given two region servers
-+ cost.setCosts(costs -> {
-+ costs[oldServer] = computeCostForRegionServer(oldServer);
-+ costs[newServer] = computeCostForRegionServer(newServer);
-+ });
-+ }
-
-- // Now return the scaled cost from data held in the stats object.
-- return costFromArray(stats);
-+ @Override
-+ protected final double cost() {
-+ return cost.cost();
- }
-
- protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList) {
-@@ -1265,18 +1250,20 @@ protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList
-
- @Override
- protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList) {
-+ Iterator<BalancerRegionLoad> iter = regionLoadList.iterator();
-+ if (!iter.hasNext()) {
-+ return 0;
-+ }
-+ double previous = getCostFromRl(iter.next());
-+ if (!iter.hasNext()) {
-+ return 0;
-+ }
- double cost = 0;
-- double previous = 0;
-- boolean isFirst = true;
-- for (BalancerRegionLoad rl : regionLoadList) {
-- double current = getCostFromRl(rl);
-- if (isFirst) {
-- isFirst = false;
-- } else {
-- cost += current - previous;
-- }
-+ do {
-+ double current = getCostFromRl(iter.next());
-+ cost += current - previous;
- previous = current;
-- }
-+ } while (iter.hasNext());
- return Math.max(0, cost / (regionLoadList.size() - 1));
- }
- }
-diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestDoubleArrayCost.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestDoubleArrayCost.java
-new file mode 100644
-index 000000000000..8dd1e4973b68
---- /dev/null
-+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestDoubleArrayCost.java
-@@ -0,0 +1,67 @@
-+/**
-+ * 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.master.balancer;
-+
-+import static org.junit.Assert.assertEquals;
-+
-+import org.apache.hadoop.hbase.HBaseClassTestRule;
-+import org.apache.hadoop.hbase.testclassification.MasterTests;
-+import org.apache.hadoop.hbase.testclassification.SmallTests;
-+import org.junit.ClassRule;
-+import org.junit.Test;
-+import org.junit.experimental.categories.Category;
-+
-+@Category({ MasterTests.class, SmallTests.class })
-+public class TestDoubleArrayCost {
-+
-+ @ClassRule
-+ public static final HBaseClassTestRule CLASS_RULE =
-+ HBaseClassTestRule.forClass(TestDoubleArrayCost.class);
-+
-+ @Test
-+ public void testComputeCost() {
-+ DoubleArrayCost cost = new DoubleArrayCost();
-+
-+ cost.prepare(100);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < 100; i++) {
-+ costs[i] = 10;
-+ }
-+ });
-+ assertEquals(0, cost.cost(), 0.01);
-+
-+ cost.prepare(101);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < 100; i++) {
-+ costs[i] = 0;
-+ }
-+ costs[100] = 100;
-+ });
-+ assertEquals(1, cost.cost(), 0.01);
-+
-+ cost.prepare(200);
-+ cost.setCosts(costs -> {
-+ for (int i = 0; i < 100; i++) {
-+ costs[i] = 0;
-+ costs[i + 100] = 100;
-+ }
-+ costs[100] = 100;
-+ });
-+ assertEquals(0.5, cost.cost(), 0.01);
-+ }
-+}
-\ No newline at end of file
-diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/TestStochasticBalancerJmxMetrics.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticBalancerJmxMetrics.java
-similarity index 95%
-rename from hbase-server/src/test/java/org/apache/hadoop/hbase/TestStochasticBalancerJmxMetrics.java
-rename to hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticBalancerJmxMetrics.java
-index 16d2c4d7c5ba..ab1c76c2e9dd 100644
---- a/hbase-server/src/test/java/org/apache/hadoop/hbase/TestStochasticBalancerJmxMetrics.java
-+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticBalancerJmxMetrics.java
-@@ -15,7 +15,7 @@
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
--package org.apache.hadoop.hbase;
-+package org.apache.hadoop.hbase.master.balancer;
-
- import static org.junit.Assert.assertTrue;
-
-@@ -35,10 +35,14 @@
- import javax.management.remote.JMXConnector;
- import javax.management.remote.JMXConnectorFactory;
- import org.apache.hadoop.conf.Configuration;
-+import org.apache.hadoop.hbase.HBaseClassTestRule;
-+import org.apache.hadoop.hbase.HBaseTestingUtility;
-+import org.apache.hadoop.hbase.HConstants;
-+import org.apache.hadoop.hbase.JMXListener;
-+import org.apache.hadoop.hbase.ServerName;
-+import org.apache.hadoop.hbase.TableName;
- import org.apache.hadoop.hbase.client.RegionInfo;
- import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
--import org.apache.hadoop.hbase.master.balancer.BalancerTestBase;
--import org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer;
- import org.apache.hadoop.hbase.testclassification.MediumTests;
- import org.apache.hadoop.hbase.testclassification.MiscTests;
- import org.apache.hadoop.hbase.util.Threads;
-@@ -199,7 +203,9 @@ public void testJmxMetrics_PerTableMode() throws Exception {
- final int count = 0;
- for (int i = 0; i < 10; i++) {
- Set<String> metrics = readJmxMetrics();
-- if (metrics != null) return metrics;
-+ if (metrics != null) {
-+ return metrics;
-+ }
- LOG.warn("Failed to get jmxmetrics... sleeping, retrying; " + i + " of " + count + " times");
- Threads.sleep(1000);
- }
-@@ -208,7 +214,6 @@ public void testJmxMetrics_PerTableMode() throws Exception {
-
- /**
- * Read the attributes from Hadoop->HBase->Master->Balancer in JMX
-- * @throws IOException
- */
- private Set<String> readJmxMetrics() throws IOException {
- JMXConnector connector = null;
-@@ -273,7 +278,9 @@ public void testJmxMetrics_PerTableMode() throws Exception {
- }
-
- private static void printMetrics(Set<String> metrics, String info) {
-- if (null != info) LOG.info("++++ ------ " + info + " ------");
-+ if (null != info) {
-+ LOG.info("++++ ------ " + info + " ------");
-+ }
-
- LOG.info("++++ metrics count = " + metrics.size());
- for (String str : metrics) {
-diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancer.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancer.java
-index b97679f0470f..ea65f96eaf51 100644
---- a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancer.java
-+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancer.java
-@@ -358,34 +358,6 @@ public void testRegionLoadCost() {
- assertEquals(2.5, result, 0.01);
- }
-
-- @Test
-- public void testCostFromArray() {
-- Configuration conf = HBaseConfiguration.create();
-- StochasticLoadBalancer.CostFromRegionLoadFunction
-- costFunction = new StochasticLoadBalancer.MemStoreSizeCostFunction(conf);
-- costFunction.init(mockCluster(new int[]{0, 0, 0, 0, 1}));
--
-- double[] statOne = new double[100];
-- for (int i =0; i < 100; i++) {
-- statOne[i] = 10;
-- }
-- assertEquals(0, costFunction.costFromArray(statOne), 0.01);
--
-- double[] statTwo= new double[101];
-- for (int i =0; i < 100; i++) {
-- statTwo[i] = 0;
-- }
-- statTwo[100] = 100;
-- assertEquals(1, costFunction.costFromArray(statTwo), 0.01);
--
-- double[] statThree = new double[200];
-- for (int i =0; i < 100; i++) {
-- statThree[i] = (0);
-- statThree[i+100] = 100;
-- }
-- assertEquals(0.5, costFunction.costFromArray(statThree), 0.01);
-- }
--
- @Test
- public void testLosingRs() throws Exception {
- int numNodes = 3;