[fix](ranger) make RangerDorisAccessController as singleton to avoid more and more ranger policy refresher

fe/fe-core/src/main/java/org/apache/doris/catalog/authorizer/ranger/doris/RangerDorisAccessController.java

@@ -46,21 +46,36 @@ public class RangerDorisAccessController extends RangerAccessController {
     private static final String GLOBAL_PRIV_FIXED_NAME = "*";
 
     private RangerBasePlugin dorisPlugin;
+
+    private static RangerDorisAccessController instance;
+
     // private static ScheduledThreadPoolExecutor logFlushTimer = ThreadPoolManager.newDaemonScheduledThreadPool(1,
     //        "ranger-doris-audit-log-flusher-timer", true);
     // private RangerHiveAuditHandler auditHandler;
 
-    public RangerDorisAccessController(String serviceName) {
+    private RangerDorisAccessController(String serviceName) {
         this(serviceName, null);
     }
 
-    public RangerDorisAccessController(String serviceName, RangerAuthContextListener rangerAuthContextListener) {
+    private RangerDorisAccessController(String serviceName, RangerAuthContextListener rangerAuthContextListener) {
         dorisPlugin = new RangerDorisPlugin(serviceName, rangerAuthContextListener);
         // auditHandler = new RangerHiveAuditHandler(dorisPlugin.getConfig());
         // start a timed log flusher
         // logFlushTimer.scheduleAtFixedRate(new RangerHiveAuditLogFlusher(auditHandler), 10, 20L, TimeUnit.SECONDS);
     }
 
+    public static RangerDorisAccessController getInstance(String serviceName) {
+        return getInstance(serviceName, null);
+    }
+
+    public static synchronized RangerDorisAccessController getInstance(String serviceName,
+            RangerAuthContextListener rangerAuthContextListener) {
+        if (instance == null) {
+            instance = new RangerDorisAccessController(serviceName, rangerAuthContextListener);
+        }
+        return instance;
+    }
+
     @VisibleForTesting
     public RangerDorisAccessController(RangerBasePlugin plugin) {
         dorisPlugin = plugin;

fe/fe-core/src/main/java/org/apache/doris/mysql/privilege/AccessControllerManager.java

@@ -58,7 +58,7 @@ public class AccessControllerManager {
     public AccessControllerManager(Auth auth) {
         this.auth = auth;
         if (Config.access_controller_type.equalsIgnoreCase("ranger-doris")) {
-            defaultAccessController = new RangerDorisAccessController("doris");
+            defaultAccessController = RangerDorisAccessController.getInstance("doris");
         } else {
             defaultAccessController = new InternalAccessController(auth);
         }