From 03c84fb9be196f423802ff8ac51e865eb37a0934 Mon Sep 17 00:00:00 2001
From: Akira Ajisaka <aajisaka@apache.org>
Date: Thu, 21 Jan 2021 10:07:46 +0900
Subject: [PATCH] HDFS-15783. Speed up
 BlockPlacementPolicyRackFaultTolerant#verifyBlockPlacement (#2626)

(cherry picked from commit 45b3a8470975e67cce0e3e4d8eb8c7b6e7b6992f)
---
 .../BlockPlacementPolicyRackFaultTolerant.java               | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyRackFaultTolerant.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyRackFaultTolerant.java
index b204450491a..dad877fdc76 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyRackFaultTolerant.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyRackFaultTolerant.java
@@ -237,9 +237,8 @@ public class BlockPlacementPolicyRackFaultTolerant extends BlockPlacementPolicyD
       // only one rack
       return new BlockPlacementStatusDefault(1, 1, 1);
     }
-    // 1. Check that all locations are different.
-    // 2. Count locations on different racks.
-    Set<String> racks = new TreeSet<>();
+    // Count locations on different racks.
+    Set<String> racks = new HashSet<>();
     for (DatanodeInfo dn : locs) {
       racks.add(dn.getNetworkLocation());
     }