Fix memory leak in worker due to message retry map (#12878)

dolphinscheduler-worker/src/main/java/org/apache/dolphinscheduler/server/worker/message/MessageRetryRunner.java

@@ -28,6 +28,7 @@ import org.apache.commons.collections.MapUtils;
 
 import java.time.Duration;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -108,11 +109,19 @@ public class MessageRetryRunner extends BaseDaemonThread {
                 }
 
                 long now = System.currentTimeMillis();
-                for (Map.Entry<Integer, Map<CommandType, BaseCommand>> taskEntry : needToRetryMessages.entrySet()) {
+                Iterator<Map.Entry<Integer, Map<CommandType, BaseCommand>>> iterator =
+                        needToRetryMessages.entrySet().iterator();
+                while (iterator.hasNext()) {
+                    Map.Entry<Integer, Map<CommandType, BaseCommand>> taskEntry = iterator.next();
                     Integer taskInstanceId = taskEntry.getKey();
+                    Map<CommandType, BaseCommand> retryMessageMap = taskEntry.getValue();
+                    if (retryMessageMap.isEmpty()) {
+                        iterator.remove();
+                        continue;
+                    }
                     LoggerUtils.setTaskInstanceIdMDC(taskInstanceId);
                     try {
-                        for (Map.Entry<CommandType, BaseCommand> messageEntry : taskEntry.getValue().entrySet()) {
+                        for (Map.Entry<CommandType, BaseCommand> messageEntry : retryMessageMap.entrySet()) {
                             CommandType messageType = messageEntry.getKey();
                             BaseCommand message = messageEntry.getValue();
                             if (now - message.getMessageSendTime() > MESSAGE_RETRY_WINDOW) {