1.修改发送机制，防止在服务端较少时，造成过多的压力。

skywalking-api/src/main/java/com/ai/cloud/skywalking/sender/DataSenderWithCopies.java

@@ -2,30 +2,37 @@ package com.ai.cloud.skywalking.sender;
 
 import static com.ai.cloud.skywalking.conf.Config.Sender.MAX_COPY_NUM;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * 带副本的数据发送器
+ * 
  * @author wusheng
  *
  */
-public class DataSenderWithCopies implements IDataSender{
+public class DataSenderWithCopies implements IDataSender {
 	private int maxCopyNum;
-	
-	private List<IDataSender> senders = new ArrayList<IDataSender>();
-	
-	public DataSenderWithCopies(int maxKeepConnectingSenderSize){
-		//最大副本数量，不能大于可用最大连接数
-		maxCopyNum = maxKeepConnectingSenderSize > MAX_COPY_NUM ? MAX_COPY_NUM: maxKeepConnectingSenderSize;
+
+	private Set<IDataSender> senders = new HashSet<IDataSender>();
+
+	public DataSenderWithCopies(int maxKeepConnectingSenderSize) {
+		// 最大副本数量，不能大于可用最大连接数
+		maxCopyNum = maxKeepConnectingSenderSize > MAX_COPY_NUM ? MAX_COPY_NUM
+				: maxKeepConnectingSenderSize;
 	}
-	
+
 	/**
 	 * 尝试增加到最大可用副本数，极端情况可能不足
+	 * 
 	 * @param dataSender
 	 * @return
 	 */
-	public boolean append(IDataSender dataSender){
+	public boolean append(IDataSender dataSender) {
+		// 出现重复sender，副本到达最大限度
+		if (senders.contains(dataSender)) {
+			return false;
+		}
 		senders.add(dataSender);
 		return senders.size() < maxCopyNum;
 	}
@@ -35,14 +42,16 @@ public class DataSenderWithCopies implements IDataSender{
 	 */
 	public boolean send(String data) {
 		int successNum = 0;
-		for(IDataSender sender : senders){
-			if(sender.send(data)){
+		for (IDataSender sender : senders) {
+			if (sender.send(data)) {
 				successNum++;
 			}
 		}
-		if(successNum >= 2 || successNum >= maxCopyNum){
+		if (senders.size() == 1 && successNum == 1) {
+			return true;
+		} else if (successNum >= 2) {
 			return true;
-		}else{
+		} else {
 			return false;
 		}
 	}