[inner-2371] fix: sql execution hang problem caused by the inability to respond to the front side due to unprocessed packets.

src/main/java/com/actiontech/dble/services/BackendService.java

@@ -131,7 +131,7 @@ public abstract class BackendService extends AbstractService {
             handleDataError(e);
         } finally {
             isHandling.set(false);
-            if (taskQueue.size() > 0) {
+            if (!taskQueue.isEmpty()) {
                 doHandle(task);
             }
         }
@@ -232,7 +232,7 @@ public abstract class BackendService extends AbstractService {
     protected void handleDataError(Exception e) {
         LOGGER.warn(this.toString() + " handle data error:", e);
         connection.close("handle data error:" + e.getMessage());
-        while (taskQueue.size() > 0) {
+        while (!taskQueue.isEmpty()) {
             clearTaskQueue();
             readSize.set(0);
             // clear all data from the client
@@ -697,8 +697,8 @@ public abstract class BackendService extends AbstractService {
                 handleDataError(e);
             } finally {
                 isHandling.set(false);
-                if (taskQueue.size() > 0) {
-                    doHandle(null);
+                if (!taskQueue.isEmpty()) {
+                    doHandle(taskQueue.peek());
                 }
             }
         }