From 64b9d2f5ab4db65ec494c1f26661e7e2bd0b8664 Mon Sep 17 00:00:00 2001
From: Viraj Jasani <vjasani@apache.org>
Date: Sat, 18 Jan 2020 17:43:46 -0800
Subject: [PATCH] HBASE-23335 : Improving cost functions array copy in
 StochasticLoadBalancer

Signed-off-by: stack <stack@apache.org>
---
 .../hbase/master/balancer/StochasticLoadBalancer.java     | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

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 b14ab4059b98..60c8b672aad1 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
@@ -414,9 +414,7 @@ public synchronized List<RegionPlan> balanceCluster(Map<ServerName,
 
     double currentCost = computeCost(cluster, Double.MAX_VALUE);
     curOverallCost = currentCost;
-    for (int i = 0; i < this.curFunctionCosts.length; i++) {
-      curFunctionCosts[i] = tempFunctionCosts[i];
-    }
+    System.arraycopy(tempFunctionCosts, 0, curFunctionCosts, 0, this.curFunctionCosts.length);
 
     double initCost = currentCost;
     double newCost = currentCost;
@@ -462,9 +460,7 @@ public synchronized List<RegionPlan> balanceCluster(Map<ServerName,
 
         // save for JMX
         curOverallCost = currentCost;
-        for (int i = 0; i < this.curFunctionCosts.length; i++) {
-          curFunctionCosts[i] = tempFunctionCosts[i];
-        }
+        System.arraycopy(tempFunctionCosts, 0, curFunctionCosts, 0, this.curFunctionCosts.length);
       } else {
         // Put things back the way they were before.
         // TODO: undo by remembering old values