diff --git a/common/src/main/java/org/apache/rocketmq/common/message/MessageConst.java b/common/src/main/java/org/apache/rocketmq/common/message/MessageConst.java
index ba9b7443cb..81b7823f3b 100644
--- a/common/src/main/java/org/apache/rocketmq/common/message/MessageConst.java
+++ b/common/src/main/java/org/apache/rocketmq/common/message/MessageConst.java
@@ -57,7 +57,7 @@ public class MessageConst {
 
     public static final String KEY_SEPARATOR = " ";
 
-    public static final HashSet<String> STRING_HASH_SET = new HashSet<String>();
+    public static final HashSet<String> STRING_HASH_SET = new HashSet<>(64);
 
     static {
         STRING_HASH_SET.add(PROPERTY_TRACE_SWITCH);