From ca13ea6a2a4f17c2be43cc0fb4b4eb8baa2da6df Mon Sep 17 00:00:00 2001
From: Roger3581321 <roger.yxt@aliyun.com>
Date: Mon, 7 Feb 2022 10:38:23 +0800
Subject: [PATCH] Use CopyOnWriteArraySet for ConnectionGroup#connectionSet to
 avoid iterator fast-fail (#2559)

---
 .../sentinel/cluster/server/connection/ConnectionGroup.java    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java b/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
index 9a3d53cd28..4fb3376084 100644
--- a/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
+++ b/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
@@ -19,6 +19,7 @@
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import com.alibaba.csp.sentinel.cluster.server.ServerConstants;
@@ -34,7 +35,7 @@ public class ConnectionGroup {
 
     private final String namespace;
 
-    private final Set<ConnectionDescriptor> connectionSet = Collections.synchronizedSet(new HashSet<ConnectionDescriptor>());
+    private final Set<ConnectionDescriptor> connectionSet = new CopyOnWriteArraySet<>();
     private final AtomicInteger connectedCount = new AtomicInteger();
 
     public ConnectionGroup(String namespace) {