Improve cache update performance

22 files changed, 443 insertions, 379 deletions

diff --git a/src/main/java/org/traccar/BaseProtocolDecoder.java b/src/main/java/org/traccar/BaseProtocolDecoder.java
index 97762e8ca..4d4086c3c 100644
--- a/src/main/java/org/traccar/BaseProtocolDecoder.java
+++ b/src/main/java/org/traccar/BaseProtocolDecoder.java
@@ -29,7 +29,6 @@ import org.traccar.model.Position;
 import org.traccar.session.ConnectionManager;
 import org.traccar.session.DeviceSession;
 import org.traccar.session.cache.CacheManager;
-import org.traccar.storage.StorageException;
 
 import jakarta.inject.Inject;
 import java.net.InetSocketAddress;
@@ -137,7 +136,7 @@ public abstract class BaseProtocolDecoder extends ExtendedObjectDecoder {
     public DeviceSession getDeviceSession(Channel channel, SocketAddress remoteAddress, String... uniqueIds) {
         try {
             return connectionManager.getDeviceSession(protocol, channel, remoteAddress, uniqueIds);
-        } catch (StorageException e) {
+        } catch (Exception e) {
             throw new RuntimeException(e);
         }
     }
diff --git a/src/main/java/org/traccar/api/BaseObjectResource.java b/src/main/java/org/traccar/api/BaseObjectResource.java
index ebfa93ff0..2a801221b 100644
--- a/src/main/java/org/traccar/api/BaseObjectResource.java
+++ b/src/main/java/org/traccar/api/BaseObjectResource.java
@@ -67,7 +67,7 @@ public abstract class BaseObjectResource<T extends BaseModel> extends BaseResour
     }
 
     @POST
-    public Response add(T entity) throws StorageException {
+    public Response add(T entity) throws Exception {
         permissionsService.checkEdit(getUserId(), entity, true);
 
         entity.setId(storage.addObject(entity, new Request(new Columns.Exclude("id"))));
@@ -85,7 +85,7 @@ public abstract class BaseObjectResource<T extends BaseModel> extends BaseResour
 
     @Path("{id}")
     @PUT
-    public Response update(T entity) throws StorageException {
+    public Response update(T entity) throws Exception {
         permissionsService.checkEdit(getUserId(), entity, false);
         permissionsService.checkPermission(baseClass, getUserId(), entity.getId());
 
@@ -111,7 +111,7 @@ public abstract class BaseObjectResource<T extends BaseModel> extends BaseResour
                         new Condition.Equals("id", entity.getId())));
             }
         }
-        cacheManager.updateOrInvalidate(true, entity, ObjectOperation.UPDATE);
+        cacheManager.invalidateObject(true, entity.getClass(), entity.getId(), ObjectOperation.UPDATE);
         LogAction.edit(getUserId(), entity);
 
         return Response.ok(entity).build();
@@ -119,12 +119,12 @@ public abstract class BaseObjectResource<T extends BaseModel> extends BaseResour
 
     @Path("{id}")
     @DELETE
-    public Response remove(@PathParam("id") long id) throws StorageException {
+    public Response remove(@PathParam("id") long id) throws Exception {
         permissionsService.checkEdit(getUserId(), baseClass, false);
         permissionsService.checkPermission(baseClass, getUserId(), id);
 
         storage.removeObject(baseClass, new Request(new Condition.Equals("id", id)));
-        cacheManager.invalidate(baseClass, id);
+        cacheManager.invalidateObject(true, baseClass, id, ObjectOperation.DELETE);
 
         LogAction.remove(getUserId(), baseClass, id);
 
diff --git a/src/main/java/org/traccar/api/resource/AttributeResource.java b/src/main/java/org/traccar/api/resource/AttributeResource.java
index 44f0ef452..52c4d6324 100644
--- a/src/main/java/org/traccar/api/resource/AttributeResource.java
+++ b/src/main/java/org/traccar/api/resource/AttributeResource.java
@@ -78,21 +78,21 @@ public class AttributeResource extends ExtendedObjectResource<Attribute> {
     }
 
     @POST
-    public Response add(Attribute entity) throws StorageException {
+    public Response add(Attribute entity) throws Exception {
         permissionsService.checkAdmin(getUserId());
         return super.add(entity);
     }
 
     @Path("{id}")
     @PUT
-    public Response update(Attribute entity) throws StorageException {
+    public Response update(Attribute entity) throws Exception {
         permissionsService.checkAdmin(getUserId());
         return super.update(entity);
     }
 
     @Path("{id}")
     @DELETE
-    public Response remove(@PathParam("id") long id) throws StorageException {
+    public Response remove(@PathParam("id") long id) throws Exception {
         permissionsService.checkAdmin(getUserId());
         return super.remove(id);
     }
diff --git a/src/main/java/org/traccar/api/resource/DeviceResource.java b/src/main/java/org/traccar/api/resource/DeviceResource.java
index ebc40a9b1..217ccda65 100644
--- a/src/main/java/org/traccar/api/resource/DeviceResource.java
+++ b/src/main/java/org/traccar/api/resource/DeviceResource.java
@@ -128,7 +128,7 @@ public class DeviceResource extends BaseObjectResource<Device> {
 
     @Path("{id}/accumulators")
     @PUT
-    public Response updateAccumulators(DeviceAccumulators entity) throws StorageException {
+    public Response updateAccumulators(DeviceAccumulators entity) throws Exception {
         if (permissionsService.notAdmin(getUserId())) {
             permissionsService.checkManager(getUserId());
             permissionsService.checkPermission(Device.class, getUserId(), entity.getDeviceId());
diff --git a/src/main/java/org/traccar/api/resource/PermissionsResource.java b/src/main/java/org/traccar/api/resource/PermissionsResource.java
index 2a8ac62f7..9e2d21f2c 100644
--- a/src/main/java/org/traccar/api/resource/PermissionsResource.java
+++ b/src/main/java/org/traccar/api/resource/PermissionsResource.java
@@ -64,7 +64,7 @@ public class PermissionsResource  extends BaseResource {
 
     @Path("bulk")
     @POST
-    public Response add(List<LinkedHashMap<String, Long>> entities) throws StorageException, ClassNotFoundException {
+    public Response add(List<LinkedHashMap<String, Long>> entities) throws Exception {
         permissionsService.checkRestriction(getUserId(), UserRestrictions::getReadonly);
         checkPermissionTypes(entities);
         for (LinkedHashMap<String, Long> entity: entities) {
@@ -84,13 +84,13 @@ public class PermissionsResource  extends BaseResource {
     }
 
     @POST
-    public Response add(LinkedHashMap<String, Long> entity) throws StorageException, ClassNotFoundException {
+    public Response add(LinkedHashMap<String, Long> entity) throws Exception {
         return add(Collections.singletonList(entity));
     }
 
     @DELETE
     @Path("bulk")
-    public Response remove(List<LinkedHashMap<String, Long>> entities) throws StorageException, ClassNotFoundException {
+    public Response remove(List<LinkedHashMap<String, Long>> entities) throws Exception {
         permissionsService.checkRestriction(getUserId(), UserRestrictions::getReadonly);
         checkPermissionTypes(entities);
         for (LinkedHashMap<String, Long> entity: entities) {
@@ -110,7 +110,7 @@ public class PermissionsResource  extends BaseResource {
     }
 
     @DELETE
-    public Response remove(LinkedHashMap<String, Long> entity) throws StorageException, ClassNotFoundException {
+    public Response remove(LinkedHashMap<String, Long> entity) throws Exception {
         return remove(Collections.singletonList(entity));
     }
 
diff --git a/src/main/java/org/traccar/api/resource/ServerResource.java b/src/main/java/org/traccar/api/resource/ServerResource.java
index 1ef2a6c33..66ecc74e1 100644
--- a/src/main/java/org/traccar/api/resource/ServerResource.java
+++ b/src/main/java/org/traccar/api/resource/ServerResource.java
@@ -107,14 +107,14 @@ public class ServerResource extends BaseResource {
     }
 
     @PUT
-    public Response update(Server entity) throws StorageException {
+    public Response update(Server server) throws Exception {
         permissionsService.checkAdmin(getUserId());
-        storage.updateObject(entity, new Request(
+        storage.updateObject(server, new Request(
                 new Columns.Exclude("id"),
-                new Condition.Equals("id", entity.getId())));
-        cacheManager.updateOrInvalidate(true, entity, ObjectOperation.UPDATE);
-        LogAction.edit(getUserId(), entity);
-        return Response.ok(entity).build();
+                new Condition.Equals("id", server.getId())));
+        cacheManager.invalidateObject(true, Server.class, server.getId(), ObjectOperation.UPDATE);
+        LogAction.edit(getUserId(), server);
+        return Response.ok(server).build();
     }
 
     @Path("geocode")
@@ -157,4 +157,11 @@ public class ServerResource extends BaseResource {
         return Response.ok().build();
     }
 
+    @Path("cache")
+    @GET
+    public String cache() throws StorageException {
+        permissionsService.checkAdmin(getUserId());
+        return cacheManager.toString();
+    }
+
 }
diff --git a/src/main/java/org/traccar/api/resource/UserResource.java b/src/main/java/org/traccar/api/resource/UserResource.java
index 99537f912..47ea9b07c 100644
--- a/src/main/java/org/traccar/api/resource/UserResource.java
+++ b/src/main/java/org/traccar/api/resource/UserResource.java
@@ -126,7 +126,7 @@ public class UserResource extends BaseObjectResource<User> {
 
     @Path("{id}")
     @DELETE
-    public Response remove(@PathParam("id") long id) throws StorageException {
+    public Response remove(@PathParam("id") long id) throws Exception {
         Response response = super.remove(id);
         if (getUserId() == id) {
             request.getSession().removeAttribute(SessionResource.USER_ID_KEY);
diff --git a/src/main/java/org/traccar/broadcast/BaseBroadcastService.java b/src/main/java/org/traccar/broadcast/BaseBroadcastService.java
index 1c4660320..01b212c60 100644
--- a/src/main/java/org/traccar/broadcast/BaseBroadcastService.java
+++ b/src/main/java/org/traccar/broadcast/BaseBroadcastService.java
@@ -69,10 +69,8 @@ public abstract class BaseBroadcastService implements BroadcastService {
     }
 
     @Override
-    public void invalidateObject(
-            boolean local,
-            Class<? extends BaseModel> clazz, long id,
-            ObjectOperation operation) {
+    public <T extends BaseModel> void invalidateObject(
+            boolean local, Class<T> clazz, long id, ObjectOperation operation) {
         BroadcastMessage message = new BroadcastMessage();
         var invalidateObject = new BroadcastMessage.InvalidateObject();
         invalidateObject.setClazz(Permission.getKey(clazz));
@@ -83,11 +81,8 @@ public abstract class BaseBroadcastService implements BroadcastService {
     }
 
     @Override
-    public void invalidatePermission(
-            boolean local,
-            Class<? extends BaseModel> clazz1, long id1,
-            Class<? extends BaseModel> clazz2, long id2,
-            boolean link) {
+    public synchronized <T1 extends BaseModel, T2 extends BaseModel> void invalidatePermission(
+            boolean local, Class<T1> clazz1, long id1, Class<T2> clazz2, long id2, boolean link) {
         BroadcastMessage message = new BroadcastMessage();
         var invalidatePermission = new BroadcastMessage.InvalidatePermission();
         invalidatePermission.setClazz1(Permission.getKey(clazz1));
@@ -101,7 +96,7 @@ public abstract class BaseBroadcastService implements BroadcastService {
 
     protected abstract void sendMessage(BroadcastMessage message);
 
-    protected void handleMessage(BroadcastMessage message) {
+    protected void handleMessage(BroadcastMessage message) throws Exception {
         if (message.getDevice() != null) {
             listeners.forEach(listener -> listener.updateDevice(false, message.getDevice()));
         } else if (message.getPosition() != null) {
@@ -112,17 +107,21 @@ public abstract class BaseBroadcastService implements BroadcastService {
             listeners.forEach(listener -> listener.updateCommand(false, message.getCommandDeviceId()));
         } else if (message.getInvalidateObject() != null) {
             var invalidateObject = message.getInvalidateObject();
-            listeners.forEach(listeners -> listeners.invalidateObject(
-                    false,
-                    Permission.getKeyClass(invalidateObject.getClazz()), invalidateObject.getId(),
-                    invalidateObject.getOperation()));
+            for (BroadcastInterface listener : listeners) {
+                listener.invalidateObject(
+                        false,
+                        Permission.getKeyClass(invalidateObject.getClazz()), invalidateObject.getId(),
+                        invalidateObject.getOperation());
+            }
         } else if (message.getInvalidatePermission() != null) {
             var invalidatePermission = message.getInvalidatePermission();
-            listeners.forEach(listener -> listener.invalidatePermission(
-                    false,
-                    Permission.getKeyClass(invalidatePermission.getClazz1()), invalidatePermission.getId1(),
-                    Permission.getKeyClass(invalidatePermission.getClazz2()), invalidatePermission.getId2(),
-                    invalidatePermission.getLink()));
+            for (BroadcastInterface listener : listeners) {
+                listener.invalidatePermission(
+                        false,
+                        Permission.getKeyClass(invalidatePermission.getClazz1()), invalidatePermission.getId1(),
+                        Permission.getKeyClass(invalidatePermission.getClazz2()), invalidatePermission.getId2(),
+                        invalidatePermission.getLink());
+            }
         }
     }
 
diff --git a/src/main/java/org/traccar/broadcast/BroadcastInterface.java b/src/main/java/org/traccar/broadcast/BroadcastInterface.java
index 25fdf4d93..d0a491cd2 100644
--- a/src/main/java/org/traccar/broadcast/BroadcastInterface.java
+++ b/src/main/java/org/traccar/broadcast/BroadcastInterface.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Anton Tananaev (anton@traccar.org)
+ * Copyright 2022 - 2023 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,16 +35,12 @@ public interface BroadcastInterface {
     default void updateCommand(boolean local, long deviceId) {
     }
 
-    default void invalidateObject(
-            boolean local,
-            Class<? extends BaseModel> clazz, long id,
-            ObjectOperation operation) {
+    default <T extends BaseModel> void invalidateObject(
+            boolean local, Class<T> clazz, long id, ObjectOperation operation) throws Exception {
     }
 
-    default void invalidatePermission(
-            boolean local,
-            Class<? extends BaseModel> clazz1, long id1,
-            Class<? extends BaseModel> clazz2, long id2,
-            boolean link) {
+    default <T1 extends BaseModel, T2 extends BaseModel> void invalidatePermission(
+            boolean local, Class<T1> clazz1, long id1, Class<T2> clazz2, long id2, boolean link) throws Exception {
     }
+
 }
diff --git a/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java b/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java
index 1c02b319b..793c6df36 100644
--- a/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java
+++ b/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java
@@ -103,7 +103,7 @@ public class MulticastBroadcastService extends BaseBroadcastService {
                 }
                 publisherSocket = null;
                 socket.leaveGroup(group, networkInterface);
-            } catch (IOException e) {
+            } catch (Exception e) {
                 throw new RuntimeException(e);
             }
         }
diff --git a/src/main/java/org/traccar/broadcast/RedisBroadcastService.java b/src/main/java/org/traccar/broadcast/RedisBroadcastService.java
index e87ad5e61..697c45a4a 100644
--- a/src/main/java/org/traccar/broadcast/RedisBroadcastService.java
+++ b/src/main/java/org/traccar/broadcast/RedisBroadcastService.java
@@ -38,7 +38,6 @@ public class RedisBroadcastService extends BaseBroadcastService {
 
     private final ExecutorService service = Executors.newSingleThreadExecutor();
 
-    private final String url;
     private final String channel = "traccar";
 
     private Jedis subscriber;
@@ -48,7 +47,7 @@ public class RedisBroadcastService extends BaseBroadcastService {
 
     public RedisBroadcastService(Config config, ObjectMapper objectMapper) throws IOException {
         this.objectMapper = objectMapper;
-        url = config.getString(Keys.BROADCAST_ADDRESS);
+        String url = config.getString(Keys.BROADCAST_ADDRESS);
 
         try {
             subscriber = new Jedis(url);
@@ -69,9 +68,7 @@ public class RedisBroadcastService extends BaseBroadcastService {
         try {
             String payload = id  + ":" + objectMapper.writeValueAsString(message);
             publisher.publish(channel, payload);
-        } catch (IOException e) {
-            LOGGER.warn("Broadcast failed", e);
-        } catch (JedisConnectionException e) {
+        } catch (IOException | JedisConnectionException e) {
             LOGGER.warn("Broadcast failed", e);
         }
     }
@@ -114,13 +111,11 @@ public class RedisBroadcastService extends BaseBroadcastService {
                             if (messageChannel.equals(channel) && parts.length == 2 && !id.equals(parts[0])) {
                                 handleMessage(objectMapper.readValue(parts[1], BroadcastMessage.class));
                             }
-                        } catch (IOException e) {
+                        } catch (Exception e) {
                             LOGGER.warn("Broadcast handleMessage failed", e);
                         }
                     }
                 }, channel);
-            } catch (JedisConnectionException e) {
-                throw new RuntimeException(e);
             } catch (JedisException e) {
                 throw new RuntimeException(e);
             }
diff --git a/src/main/java/org/traccar/database/NotificationManager.java b/src/main/java/org/traccar/database/NotificationManager.java
index 79585d67a..45263ff3c 100644
--- a/src/main/java/org/traccar/database/NotificationManager.java
+++ b/src/main/java/org/traccar/database/NotificationManager.java
@@ -29,7 +29,6 @@ import org.traccar.model.Device;
 import org.traccar.model.Event;
 import org.traccar.model.Geofence;
 import org.traccar.model.Maintenance;
-import org.traccar.model.Notification;
 import org.traccar.model.Position;
 import org.traccar.notification.MessageException;
 import org.traccar.notification.NotificatorManager;
@@ -88,7 +87,7 @@ public class NotificationManager {
             return;
         }
 
-        var notifications = cacheManager.getDeviceObjects(event.getDeviceId(), Notification.class).stream()
+        var notifications = cacheManager.getDeviceNotifications(event.getDeviceId())
                 .filter(notification -> notification.getType().equals(event.getType()))
                 .filter(notification -> {
                     if (event.getType().equals(Event.TYPE_ALARM)) {
@@ -162,7 +161,7 @@ public class NotificationManager {
             try {
                 cacheManager.addDevice(event.getDeviceId());
                 updateEvent(event, position);
-            } catch (StorageException e) {
+            } catch (Exception e) {
                 throw new RuntimeException(e);
             } finally {
                 cacheManager.removeDevice(event.getDeviceId());
diff --git a/src/main/java/org/traccar/notificators/NotificatorFirebase.java b/src/main/java/org/traccar/notificators/NotificatorFirebase.java
index a39683b2b..d75eb21a9 100644
--- a/src/main/java/org/traccar/notificators/NotificatorFirebase.java
+++ b/src/main/java/org/traccar/notificators/NotificatorFirebase.java
@@ -24,7 +24,6 @@ import com.google.firebase.messaging.AndroidNotification;
 import com.google.firebase.messaging.ApnsConfig;
 import com.google.firebase.messaging.Aps;
 import com.google.firebase.messaging.FirebaseMessaging;
-import com.google.firebase.messaging.FirebaseMessagingException;
 import com.google.firebase.messaging.MessagingErrorCode;
 import com.google.firebase.messaging.MulticastMessage;
 import org.slf4j.Logger;
@@ -40,7 +39,6 @@ import org.traccar.notification.MessageException;
 import org.traccar.notification.NotificationFormatter;
 import org.traccar.session.cache.CacheManager;
 import org.traccar.storage.Storage;
-import org.traccar.storage.StorageException;
 import org.traccar.storage.query.Columns;
 import org.traccar.storage.query.Condition;
 import org.traccar.storage.query.Request;
@@ -136,9 +134,9 @@ public class NotificatorFirebase implements Notificator {
                     storage.updateObject(user, new Request(
                             new Columns.Include("attributes"),
                             new Condition.Equals("id", user.getId())));
-                    cacheManager.updateOrInvalidate(true, user, ObjectOperation.UPDATE);
+                    cacheManager.invalidateObject(true, User.class, user.getId(), ObjectOperation.UPDATE);
                 }
-            } catch (FirebaseMessagingException | StorageException e) {
+            } catch (Exception e) {
                 LOGGER.warn("Firebase error", e);
             }
         }
diff --git a/src/main/java/org/traccar/notificators/NotificatorTraccar.java b/src/main/java/org/traccar/notificators/NotificatorTraccar.java
index 82e1584a5..717742a1e 100644
--- a/src/main/java/org/traccar/notificators/NotificatorTraccar.java
+++ b/src/main/java/org/traccar/notificators/NotificatorTraccar.java
@@ -27,7 +27,6 @@ import org.traccar.model.User;
 import org.traccar.notification.NotificationFormatter;
 import org.traccar.session.cache.CacheManager;
 import org.traccar.storage.Storage;
-import org.traccar.storage.StorageException;
 import org.traccar.storage.query.Columns;
 import org.traccar.storage.query.Condition;
 import org.traccar.storage.query.Request;
@@ -129,9 +128,9 @@ public class NotificatorTraccar implements Notificator {
                     storage.updateObject(user, new Request(
                             new Columns.Include("attributes"),
                             new Condition.Equals("id", user.getId())));
-                    cacheManager.updateOrInvalidate(true, user, ObjectOperation.UPDATE);
+                    cacheManager.invalidateObject(true, User.class, user.getId(), ObjectOperation.UPDATE);
                 }
-            } catch (StorageException e) {
+            } catch (Exception e) {
                 LOGGER.warn("Push error", e);
             }
         }
diff --git a/src/main/java/org/traccar/session/ConnectionManager.java b/src/main/java/org/traccar/session/ConnectionManager.java
index 0b13a5a72..3716fdf9a 100644
--- a/src/main/java/org/traccar/session/ConnectionManager.java
+++ b/src/main/java/org/traccar/session/ConnectionManager.java
@@ -102,7 +102,7 @@ public class ConnectionManager implements BroadcastInterface {
 
     public DeviceSession getDeviceSession(
             Protocol protocol, Channel channel, SocketAddress remoteAddress,
-            String... uniqueIds) throws StorageException {
+            String... uniqueIds) throws Exception {
 
         Endpoint endpoint = new Endpoint(channel, remoteAddress);
         Map<String, DeviceSession> endpointSessions = sessionsByEndpoint.getOrDefault(
@@ -327,11 +327,8 @@ public class ConnectionManager implements BroadcastInterface {
     }
 
     @Override
-    public synchronized void invalidatePermission(
-            boolean local,
-            Class<? extends BaseModel> clazz1, long id1,
-            Class<? extends BaseModel> clazz2, long id2,
-            boolean link) {
+    public synchronized <T1 extends BaseModel, T2 extends BaseModel> void invalidatePermission(
+            boolean local, Class<T1> clazz1, long id1, Class<T2> clazz2, long id2, boolean link) {
         if (link && clazz1.equals(User.class) && clazz2.equals(Device.class)) {
             if (listeners.containsKey(id1)) {
                 userDevices.get(id1).add(id2);
diff --git a/src/main/java/org/traccar/session/cache/CacheGraph.java b/src/main/java/org/traccar/session/cache/CacheGraph.java
new file mode 100644
index 000000000..c99997288
--- /dev/null
+++ b/src/main/java/org/traccar/session/cache/CacheGraph.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2023 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.session.cache;
+
+import org.traccar.model.BaseModel;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+
+public class CacheGraph {
+
+    private final Map<CacheKey, CacheNode> roots = new HashMap<>();
+    private final WeakValueMap<CacheKey, CacheNode> nodes = new WeakValueMap<>();
+
+    void addObject(BaseModel value) {
+        CacheKey key = new CacheKey(value);
+        CacheNode node = new CacheNode(value);
+        roots.put(key, node);
+        nodes.put(key, node);
+    }
+
+    void removeObject(Class<? extends BaseModel> clazz, long id) {
+        CacheKey key = new CacheKey(clazz, id);
+        CacheNode node = nodes.remove(key);
+        if (node != null) {
+            node.getAllLinks(false).forEach(child -> child.getLinks(key.getClazz(), true).remove(node));
+        }
+        roots.remove(key);
+    }
+
+    @SuppressWarnings("unchecked")
+    <T extends BaseModel> T getObject(Class<T> clazz, long id) {
+        CacheNode node = nodes.get(new CacheKey(clazz, id));
+        return node != null ? (T) node.getValue() : null;
+    }
+
+    <T extends BaseModel> Stream<T> getObjects(
+            Class<? extends BaseModel> fromClass, long fromId,
+            Class<T> clazz, Set<Class<? extends BaseModel>> proxies, boolean forward) {
+
+        CacheNode rootNode = nodes.get(new CacheKey(fromClass, fromId));
+        if (rootNode != null) {
+            return getObjectStream(rootNode, clazz, proxies, forward);
+        } else {
+            return Stream.empty();
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private <T extends BaseModel> Stream<T> getObjectStream(
+            CacheNode rootNode, Class<T> clazz, Set<Class<? extends BaseModel>> proxies, boolean forward) {
+
+        if (proxies.contains(clazz)) {
+            return Stream.empty();
+        }
+
+        var directSteam = rootNode.getLinks(clazz, forward).stream()
+                .map(node -> (T) node.getValue());
+
+        var proxyStream = proxies.stream()
+                .flatMap(proxyClass -> rootNode.getLinks(proxyClass, forward).stream()
+                        .flatMap(node -> getObjectStream(node, clazz, proxies, forward)));
+
+        return Stream.concat(directSteam, proxyStream);
+    }
+
+    void updateObject(BaseModel value) {
+        CacheNode node = nodes.get(new CacheKey(value));
+        if (node != null) {
+            node.setValue(value);
+        }
+    }
+
+    boolean addLink(
+            Class<? extends BaseModel> fromClazz, long fromId,
+            BaseModel toValue) {
+        boolean stop = true;
+        CacheNode fromNode = nodes.get(new CacheKey(fromClazz, fromId));
+        if (fromNode != null) {
+            CacheKey toKey = new CacheKey(toValue);
+            CacheNode toNode = nodes.get(toKey);
+            if (toNode == null) {
+                stop = false;
+                toNode = new CacheNode(toValue);
+                nodes.put(toKey, toNode);
+            }
+            fromNode.getLinks(toValue.getClass(), true).add(toNode);
+            toNode.getLinks(fromClazz, false).add(fromNode);
+        }
+        return stop;
+    }
+
+    void removeLink(
+            Class<? extends BaseModel> fromClazz, long fromId,
+            Class<? extends BaseModel> toClazz, long toId) {
+        CacheNode fromNode = nodes.get(new CacheKey(fromClazz, fromId));
+        if (fromNode != null) {
+            CacheNode toNode = nodes.get(new CacheKey(toClazz, toId));
+            if (toNode != null) {
+                fromNode.getLinks(toClazz, true).remove(toNode);
+                toNode.getLinks(fromClazz, false).remove(fromNode);
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder();
+        for (CacheNode node : roots.values()) {
+            printNode(stringBuilder, node, "");
+        }
+        return stringBuilder.toString().trim();
+    }
+
+    private void printNode(StringBuilder stringBuilder, CacheNode node, String indentation) {
+        stringBuilder
+                .append('\n')
+                .append(indentation)
+                .append(node.getValue().getClass().getSimpleName())
+                .append('(').append(node.getValue().getId()).append(')');
+        node.getAllLinks(true).forEach(child -> printNode(stringBuilder, child, indentation + "  "));
+    }
+
+}
diff --git a/src/main/java/org/traccar/session/cache/CacheKey.java b/src/main/java/org/traccar/session/cache/CacheKey.java
index 23145e34b..f27d5fbf5 100644
--- a/src/main/java/org/traccar/session/cache/CacheKey.java
+++ b/src/main/java/org/traccar/session/cache/CacheKey.java
@@ -33,6 +33,10 @@ class CacheKey {
         this.id = id;
     }
 
+    public Class<? extends BaseModel> getClazz() {
+        return clazz;
+    }
+
     public boolean classIs(Class<? extends BaseModel> clazz) {
         return clazz.equals(this.clazz);
     }
diff --git a/src/main/java/org/traccar/session/cache/CacheManager.java b/src/main/java/org/traccar/session/cache/CacheManager.java
index dc9c86ef3..918c97c66 100644
--- a/src/main/java/org/traccar/session/cache/CacheManager.java
+++ b/src/main/java/org/traccar/session/cache/CacheManager.java
@@ -15,11 +15,10 @@
  */
 package org.traccar.session.cache;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import jakarta.inject.Inject;
+import jakarta.inject.Singleton;
 import org.traccar.broadcast.BroadcastInterface;
 import org.traccar.broadcast.BroadcastService;
-import org.traccar.model.ObjectOperation;
 import org.traccar.config.Config;
 import org.traccar.model.Attribute;
 import org.traccar.model.BaseModel;
@@ -31,6 +30,8 @@ import org.traccar.model.Group;
 import org.traccar.model.GroupedModel;
 import org.traccar.model.Maintenance;
 import org.traccar.model.Notification;
+import org.traccar.model.ObjectOperation;
+import org.traccar.model.Permission;
 import org.traccar.model.Position;
 import org.traccar.model.Schedulable;
 import org.traccar.model.Server;
@@ -41,30 +42,20 @@ import org.traccar.storage.query.Columns;
 import org.traccar.storage.query.Condition;
 import org.traccar.storage.query.Request;
 
-import jakarta.inject.Inject;
-import jakarta.inject.Singleton;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedHashSet;
-import java.util.LinkedList;
-import java.util.List;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 @Singleton
 public class CacheManager implements BroadcastInterface {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(CacheManager.class);
-    private static final int GROUP_DEPTH_LIMIT = 3;
-    private static final Collection<Class<? extends BaseModel>> CLASSES = Arrays.asList(
-            Attribute.class, Driver.class, Geofence.class, Maintenance.class, Notification.class);
+    private static final Set<Class<? extends BaseModel>> GROUPED_CLASSES =
+            Set.of(Attribute.class, Driver.class, Geofence.class, Maintenance.class, Notification.class);
 
     private final Config config;
     private final Storage storage;
@@ -72,24 +63,26 @@ public class CacheManager implements BroadcastInterface {
 
     private final ReadWriteLock lock = new ReentrantReadWriteLock();
 
-    private final Map<CacheKey, CacheValue> deviceCache = new HashMap<>();
-    private final Map<Long, Integer> deviceReferences = new HashMap<>();
-    private final Map<Long, Map<Class<? extends BaseModel>, Set<Long>>> deviceLinks = new HashMap<>();
-    private final Map<Long, Position> devicePositions = new HashMap<>();
+    private final CacheGraph graph = new CacheGraph();
 
     private Server server;
-    private final Map<Long, List<User>> notificationUsers = new HashMap<>();
+    private final Map<Long, Position> devicePositions = new HashMap<>();
+    private final Map<Long, AtomicInteger> deviceReferences = new HashMap<>();
 
     @Inject
     public CacheManager(Config config, Storage storage, BroadcastService broadcastService) throws StorageException {
         this.config = config;
         this.storage = storage;
         this.broadcastService = broadcastService;
-        invalidateServer();
-        invalidateUsers();
+        server = storage.getObject(Server.class, new Request(new Columns.All()));
         broadcastService.registerListener(this);
     }
 
+    @Override
+    public String toString() {
+        return graph.toString();
+    }
+
     public Config getConfig() {
         return config;
     }
@@ -97,29 +90,17 @@ public class CacheManager implements BroadcastInterface {
     public <T extends BaseModel> T getObject(Class<T> clazz, long id) {
         try {
             lock.readLock().lock();
-            var cacheValue = deviceCache.get(new CacheKey(clazz, id));
-            return cacheValue != null ? cacheValue.getValue() : null;
+            return graph.getObject(clazz, id);
         } finally {
             lock.readLock().unlock();
         }
     }
 
-    public <T extends BaseModel> List<T> getDeviceObjects(long deviceId, Class<T> clazz) {
+    public <T extends BaseModel> Set<T> getDeviceObjects(long deviceId, Class<T> clazz) {
         try {
             lock.readLock().lock();
-            var links = deviceLinks.get(deviceId);
-            if (links != null) {
-                return links.getOrDefault(clazz, new LinkedHashSet<>()).stream()
-                        .map(id -> {
-                            var cacheValue = deviceCache.get(new CacheKey(clazz, id));
-                            return cacheValue != null ? cacheValue.<T>getValue() : null;
-                        })
-                        .filter(Objects::nonNull)
-                        .collect(Collectors.toList());
-            } else {
-                LOGGER.warn("Device {} cache missing", deviceId);
-                return Collections.emptyList();
-            }
+            return graph.getObjects(Device.class, deviceId, clazz, Set.of(Group.class), true)
+                    .collect(Collectors.toUnmodifiableSet());
         } finally {
             lock.readLock().unlock();
         }
@@ -143,30 +124,40 @@ public class CacheManager implements BroadcastInterface {
         }
     }
 
-    public List<User> getNotificationUsers(long notificationId, long deviceId) {
+    public Set<User> getNotificationUsers(long notificationId, long deviceId) {
+        try {
+            lock.readLock().lock();
+            Set<User> deviceUsers = getDeviceObjects(deviceId, User.class);
+            return graph.getObjects(Notification.class, notificationId, User.class, Set.of(), false)
+                    .filter(deviceUsers::contains)
+                    .collect(Collectors.toUnmodifiableSet());
+        } finally {
+            lock.readLock().unlock();
+        }
+    }
+
+    public Stream<Notification> getDeviceNotifications(long deviceId) {
         try {
             lock.readLock().lock();
-            var users = deviceLinks.get(deviceId).get(User.class).stream()
+            var direct = graph.getObjects(Device.class, deviceId, Notification.class, Set.of(Group.class), true)
+                    .map(BaseModel::getId)
                     .collect(Collectors.toUnmodifiableSet());
-            return notificationUsers.getOrDefault(notificationId, new LinkedList<>()).stream()
-                    .filter(user -> users.contains(user.getId()))
-                    .collect(Collectors.toUnmodifiableList());
+            return graph.getObjects(Device.class, deviceId, Notification.class, Set.of(Group.class, User.class), true)
+                    .filter(notification -> notification.getAlways() || direct.contains(notification.getId()));
         } finally {
             lock.readLock().unlock();
         }
     }
 
-    public void addDevice(long deviceId) throws StorageException {
+    public void addDevice(long deviceId) throws Exception {
         try {
             lock.writeLock().lock();
-            Integer references = deviceReferences.get(deviceId);
-            if (references != null) {
-                references += 1;
-            } else {
-                unsafeAddDevice(deviceId);
-                references = 1;
+            if (deviceReferences.computeIfAbsent(deviceId, k -> new AtomicInteger()).getAndIncrement() <= 0) {
+                Device device = storage.getObject(Device.class, new Request(
+                        new Columns.All(), new Condition.Equals("id", deviceId)));
+                graph.addObject(device);
+                initializeCache(device);
             }
-            deviceReferences.put(deviceId, references);
         } finally {
             lock.writeLock().unlock();
         }
@@ -175,15 +166,10 @@ public class CacheManager implements BroadcastInterface {
     public void removeDevice(long deviceId) {
         try {
             lock.writeLock().lock();
-            Integer references = deviceReferences.get(deviceId);
-            if (references != null) {
-                references -= 1;
-                if (references <= 0) {
-                    unsafeRemoveDevice(deviceId);
-                    deviceReferences.remove(deviceId);
-                } else {
-                    deviceReferences.put(deviceId, references);
-                }
+            if (deviceReferences.computeIfAbsent(deviceId, k -> new AtomicInteger()).incrementAndGet() <= 0) {
+                graph.removeObject(Device.class, deviceId);
+                devicePositions.remove(deviceId);
+                deviceReferences.remove(deviceId);
             }
         } finally {
             lock.writeLock().unlock();
@@ -193,7 +179,7 @@ public class CacheManager implements BroadcastInterface {
     public void updatePosition(Position position) {
         try {
             lock.writeLock().lock();
-            if (deviceLinks.containsKey(position.getDeviceId())) {
+            if (deviceReferences.containsKey(position.getDeviceId())) {
                 devicePositions.put(position.getDeviceId(), position);
             }
         } finally {
@@ -202,226 +188,140 @@ public class CacheManager implements BroadcastInterface {
     }
 
     @Override
-    public void invalidateObject(
-            boolean local,
-            Class<? extends BaseModel> clazz, long id,
-            ObjectOperation operation) {
-        try {
-            var object = storage.getObject(clazz, new Request(
-                    new Columns.All(), new Condition.Equals("id", id)));
-            if (object != null) {
-                updateOrInvalidate(local, object, operation);
-            } else {
-                invalidate(clazz, id);
-            }
-        } catch (StorageException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    public <T extends BaseModel> void updateOrInvalidate(
-            boolean local, T object, ObjectOperation operation) throws StorageException {
+    public <T extends BaseModel> void invalidateObject(
+            boolean local, Class<T> clazz, long id, ObjectOperation operation) throws Exception {
         if (local) {
-            broadcastService.invalidateObject(true, object.getClass(), object.getId(), operation);
+            broadcastService.invalidateObject(true, clazz, id, operation);
         }
 
-        if (object instanceof Server) {
-            invalidateServer();
+        if (operation == ObjectOperation.DELETE) {
+            graph.removeObject(clazz, id);
+        }
+        if (operation != ObjectOperation.UPDATE) {
             return;
         }
-        if (object instanceof User) {
-            invalidateUsers();
+
+        if (clazz.equals(Server.class)) {
+            server = storage.getObject(Server.class, new Request(new Columns.All()));
             return;
         }
 
-        boolean invalidate = false;
-        var before = getObject(object.getClass(), object.getId());
+        var after = storage.getObject(clazz, new Request(new Columns.All(), new Condition.Equals("id", id)));
+        if (after == null) {
+            return;
+        }
+        var before = getObject(after.getClass(), after.getId());
         if (before == null) {
             return;
-        } else if (object instanceof GroupedModel) {
-            if (((GroupedModel) before).getGroupId() != ((GroupedModel) object).getGroupId()) {
-                invalidate = true;
-            }
-        } else if (object instanceof Schedulable) {
-            if (((Schedulable) before).getCalendarId() != ((Schedulable) object).getCalendarId()) {
-                invalidate = true;
-            }
         }
-        if (invalidate) {
-            invalidate(object.getClass(), object.getId());
-        } else {
-            try {
-                lock.writeLock().lock();
-                deviceCache.get(new CacheKey(object.getClass(), object.getId())).setValue(object);
-            } finally {
-                lock.writeLock().unlock();
+
+        if (after instanceof GroupedModel) {
+            long beforeGroupId = ((GroupedModel) before).getGroupId();
+            long afterGroupId = ((GroupedModel) after).getGroupId();
+            if (beforeGroupId != afterGroupId) {
+                if (beforeGroupId > 0) {
+                    invalidatePermission(clazz, id, Group.class, beforeGroupId, false);
+                }
+                if (afterGroupId > 0) {
+                    invalidatePermission(clazz, id, Group.class, afterGroupId, true);
+                }
             }
+        } else if (after instanceof Schedulable) {
+            long beforeCalendarId = ((Schedulable) before).getCalendarId();
+            long afterCalendarId = ((Schedulable) after).getCalendarId();
+            if (beforeCalendarId != afterCalendarId) {
+                if (beforeCalendarId > 0) {
+                    invalidatePermission(clazz, id, Calendar.class, beforeCalendarId, false);
+                }
+                if (afterCalendarId > 0) {
+                    invalidatePermission(clazz, id, Calendar.class, afterCalendarId, true);
+                }
+            }
+            // TODO handle notification always change
         }
-    }
 
-    public <T extends BaseModel> void invalidate(Class<T> clazz, long id) throws StorageException {
-        invalidate(new CacheKey(clazz, id));
+        graph.updateObject(after);
     }
 
     @Override
-    public void invalidatePermission(
-            boolean local,
-            Class<? extends BaseModel> clazz1, long id1,
-            Class<? extends BaseModel> clazz2, long id2,
-            boolean link) {
+    public <T1 extends BaseModel, T2 extends BaseModel> void invalidatePermission(
+            boolean local, Class<T1> clazz1, long id1, Class<T2> clazz2, long id2, boolean link) throws Exception {
         if (local) {
             broadcastService.invalidatePermission(true, clazz1, id1, clazz2, id2, link);
         }
 
-        try {
-            invalidate(new CacheKey(clazz1, id1), new CacheKey(clazz2, id2));
-        } catch (StorageException e) {
-            throw new RuntimeException(e);
+        if (clazz1.equals(User.class) && GroupedModel.class.isAssignableFrom(clazz2)) {
+            invalidatePermission(clazz2, id2, clazz1, id1, link);
+        } else {
+            invalidatePermission(clazz1, id1, clazz2, id2, link);
         }
     }
 
-    private void invalidateServer() throws StorageException {
-        server = storage.getObject(Server.class, new Request(new Columns.All()));
-    }
+    private <T1 extends BaseModel, T2 extends BaseModel> void invalidatePermission(
+            Class<T1> fromClass, long fromId, Class<T2> toClass, long toId, boolean link) throws Exception {
 
-    private void invalidateUsers() throws StorageException {
-        notificationUsers.clear();
-        Map<Long, User> users = new HashMap<>();
-        storage.getObjects(User.class, new Request(new Columns.All()))
-                .forEach(user -> users.put(user.getId(), user));
-        storage.getPermissions(User.class, Notification.class).forEach(permission -> {
-            long notificationId = permission.getPropertyId();
-            var user = users.get(permission.getOwnerId());
-            notificationUsers.computeIfAbsent(notificationId, k -> new LinkedList<>()).add(user);
-        });
-    }
+        boolean groupLink = GroupedModel.class.isAssignableFrom(fromClass) && toClass.equals(Group.class);
+        boolean calendarLink = Schedulable.class.isAssignableFrom(fromClass) && toClass.equals(Calendar.class);
+        boolean userLink = fromClass.equals(User.class) && toClass.equals(Notification.class);
 
-    private void addObject(long deviceId, BaseModel object) {
-        deviceCache.computeIfAbsent(new CacheKey(object), k -> new CacheValue(object)).retain(deviceId);
-    }
+        boolean groupedLinks = GroupedModel.class.isAssignableFrom(fromClass)
+                && (GROUPED_CLASSES.contains(toClass) || toClass.equals(User.class));
 
-    private void unsafeAddDevice(long deviceId) throws StorageException {
-        Map<Class<? extends BaseModel>, Set<Long>> links = new HashMap<>();
-
-        Device device = storage.getObject(Device.class, new Request(
-                new Columns.All(), new Condition.Equals("id", deviceId)));
-        if (device != null) {
-            addObject(deviceId, device);
-            if (device.getCalendarId() > 0) {
-                var calendar = storage.getObject(Calendar.class, new Request(
-                        new Columns.All(), new Condition.Equals("id", device.getCalendarId())));
-                links.computeIfAbsent(Calendar.class, k -> new LinkedHashSet<>()).add(calendar.getId());
-                addObject(deviceId, calendar);
-            }
+        if (!groupLink && !calendarLink && !userLink && !groupedLinks) {
+            return;
+        }
 
-            int groupDepth = 0;
-            long groupId = device.getGroupId();
-            while (groupDepth < GROUP_DEPTH_LIMIT && groupId > 0) {
-                Group group = storage.getObject(Group.class, new Request(
-                        new Columns.All(), new Condition.Equals("id", groupId)));
-                links.computeIfAbsent(Group.class, k -> new LinkedHashSet<>()).add(group.getId());
-                addObject(deviceId, group);
-                groupId = group.getGroupId();
-                groupDepth += 1;
+        if (link) {
+            BaseModel object = storage.getObject(toClass, new Request(
+                    new Columns.All(), new Condition.Equals("id", toId)));
+            if (!graph.addLink(fromClass, fromId, object)) {
+                initializeCache(object);
             }
+        } else {
+            graph.removeLink(fromClass, fromId, toClass, toId);
+        }
+    }
 
-            for (Class<? extends BaseModel> clazz : CLASSES) {
-                var objects = storage.getObjects(clazz, new Request(
-                        new Columns.All(), new Condition.Permission(Device.class, deviceId, clazz)));
-                links.put(clazz, objects.stream().map(BaseModel::getId).collect(Collectors.toSet()));
-                for (var object : objects) {
-                    addObject(deviceId, object);
-                    if (object instanceof Schedulable) {
-                        var scheduled = (Schedulable) object;
-                        if (scheduled.getCalendarId() > 0) {
-                            var calendar = storage.getObject(Calendar.class, new Request(
-                                    new Columns.All(), new Condition.Equals("id", scheduled.getCalendarId())));
-                            links.computeIfAbsent(Calendar.class, k -> new LinkedHashSet<>()).add(calendar.getId());
-                            addObject(deviceId, calendar);
-                        }
-                    }
+    private void initializeCache(BaseModel object) throws Exception {
+        if (object instanceof User) {
+            for (Permission permission : storage.getPermissions(User.class, Notification.class)) {
+                if (permission.getOwnerId() == object.getId()) {
+                    invalidatePermission(
+                            permission.getOwnerClass(), permission.getOwnerId(),
+                            permission.getPropertyClass(), permission.getPropertyId(), true);
                 }
             }
+        } else {
+            if (object instanceof GroupedModel) {
+                long groupId = ((GroupedModel) object).getGroupId();
+                if (groupId > 0) {
+                    invalidatePermission(object.getClass(), object.getId(), Group.class, groupId, true);
+                }
 
-            var users = storage.getObjects(User.class, new Request(
-                    new Columns.All(), new Condition.Permission(User.class, Device.class, deviceId)));
-            links.put(User.class, users.stream().map(BaseModel::getId).collect(Collectors.toSet()));
-            for (var user : users) {
-                addObject(deviceId, user);
-                var notifications = storage.getObjects(Notification.class, new Request(
-                        new Columns.All(),
-                        new Condition.Permission(User.class, user.getId(), Notification.class))).stream()
-                        .filter(Notification::getAlways)
-                        .collect(Collectors.toList());
-                for (var notification : notifications) {
-                    links.computeIfAbsent(Notification.class, k -> new LinkedHashSet<>()).add(notification.getId());
-                    addObject(deviceId, notification);
-                    if (notification.getCalendarId() > 0) {
-                        var calendar = storage.getObject(Calendar.class, new Request(
-                                new Columns.All(), new Condition.Equals("id", notification.getCalendarId())));
-                        links.computeIfAbsent(Calendar.class, k -> new LinkedHashSet<>()).add(calendar.getId());
-                        addObject(deviceId, calendar);
+                for (Permission permission : storage.getPermissions(User.class, object.getClass())) {
+                    if (permission.getPropertyId() == object.getId()) {
+                        invalidatePermission(
+                                object.getClass(), object.getId(), User.class, permission.getOwnerId(), true);
                     }
                 }
-            }
-
-            deviceLinks.put(deviceId, links);
 
-            if (device.getPositionId() > 0) {
-                devicePositions.put(deviceId, storage.getObject(Position.class, new Request(
-                        new Columns.All(), new Condition.Equals("id", device.getPositionId()))));
+                for (Class<? extends BaseModel> clazz : GROUPED_CLASSES) {
+                    for (Permission permission : storage.getPermissions(object.getClass(), clazz)) {
+                        if (permission.getOwnerId() == object.getId()) {
+                            invalidatePermission(
+                                    object.getClass(), object.getId(), clazz, permission.getPropertyId(), true);
+                        }
+                    }
+                }
             }
-        }
-    }
 
-    private void unsafeRemoveDevice(long deviceId) {
-        deviceCache.remove(new CacheKey(Device.class, deviceId));
-        deviceLinks.remove(deviceId).forEach((clazz, ids) -> ids.forEach(id -> {
-            var key = new CacheKey(clazz, id);
-            deviceCache.computeIfPresent(key, (k, value) -> {
-                value.release(deviceId);
-                return value.getReferences().isEmpty() ? null : value;
-            });
-        }));
-        devicePositions.remove(deviceId);
-    }
-
-    private void invalidate(CacheKey... keys) throws StorageException {
-        try {
-            lock.writeLock().lock();
-            unsafeInvalidate(keys);
-        } finally {
-            lock.writeLock().unlock();
-        }
-    }
-
-    private void unsafeInvalidate(CacheKey[] keys) throws StorageException {
-        boolean invalidateServer = false;
-        boolean invalidateUsers = false;
-        Set<Long> linkedDevices = new HashSet<>();
-        for (var key : keys) {
-            if (key.classIs(Server.class)) {
-                invalidateServer = true;
-            } else {
-                if (key.classIs(User.class) || key.classIs(Notification.class)) {
-                    invalidateUsers = true;
+            if (object instanceof Schedulable) {
+                long calendarId = ((Schedulable) object).getCalendarId();
+                if (calendarId > 0) {
+                    invalidatePermission(object.getClass(), object.getId(), Calendar.class, calendarId, true);
                 }
-                deviceCache.computeIfPresent(key, (k, value) -> {
-                    linkedDevices.addAll(value.getReferences());
-                    return value;
-                });
             }
         }
-        for (long deviceId : linkedDevices) {
-            unsafeRemoveDevice(deviceId);
-            unsafeAddDevice(deviceId);
-        }
-        if (invalidateServer) {
-            invalidateServer();
-        }
-        if (invalidateUsers) {
-            invalidateUsers();
-        }
     }
 
 }
diff --git a/src/main/java/org/traccar/session/cache/CacheNode.java b/src/main/java/org/traccar/session/cache/CacheNode.java
new file mode 100644
index 000000000..7b584f81a
--- /dev/null
+++ b/src/main/java/org/traccar/session/cache/CacheNode.java
@@ -0,0 +1,40 @@
+package org.traccar.session.cache;
+
+import org.traccar.model.BaseModel;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+
+public class CacheNode {
+
+    private BaseModel value;
+
+    private final Map<Class<? extends BaseModel>, Set<CacheNode>> links = new HashMap<>();
+    private final Map<Class<? extends BaseModel>, Set<CacheNode>> backlinks = new HashMap<>();
+
+    public CacheNode(BaseModel value) {
+        this.value = value;
+    }
+
+    public BaseModel getValue() {
+        return value;
+    }
+
+    public void setValue(BaseModel value) {
+        this.value = value;
+    }
+
+    public Set<CacheNode> getLinks(Class<? extends BaseModel> clazz, boolean forward) {
+        var map = forward ? links : backlinks;
+        return map.computeIfAbsent(clazz, k -> new HashSet<>());
+    }
+
+    public Stream<CacheNode> getAllLinks(boolean forward) {
+        var map = forward ? links : backlinks;
+        return map.values().stream().flatMap(Set::stream);
+    }
+
+}
diff --git a/src/main/java/org/traccar/session/cache/CacheValue.java b/src/main/java/org/traccar/session/cache/CacheValue.java
deleted file mode 100644
index 1f0383ce5..000000000
--- a/src/main/java/org/traccar/session/cache/CacheValue.java
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Copyright 2022 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.session.cache;
-
-import org.traccar.model.BaseModel;
-
-import java.util.HashSet;
-import java.util.Set;
-
-class CacheValue {
-
-    private BaseModel value;
-    private final Set<Long> references = new HashSet<>();
-
-    CacheValue(BaseModel value) {
-        this.value = value;
-    }
-
-    public void retain(long deviceId) {
-        references.add(deviceId);
-    }
-
-    public void release(long deviceId) {
-        references.remove(deviceId);
-    }
-
-    @SuppressWarnings("unchecked")
-    public <T extends BaseModel> T getValue() {
-        return (T) value;
-    }
-
-    public void setValue(BaseModel value) {
-        this.value = value;
-    }
-
-    public Set<Long> getReferences() {
-        return references;
-    }
-
-}
diff --git a/src/main/java/org/traccar/session/cache/WeakValueMap.java b/src/main/java/org/traccar/session/cache/WeakValueMap.java
new file mode 100644
index 000000000..8323e2c30
--- /dev/null
+++ b/src/main/java/org/traccar/session/cache/WeakValueMap.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.session.cache;
+
+import java.lang.ref.WeakReference;
+import java.util.HashMap;
+import java.util.Map;
+
+public class WeakValueMap<K, V> {
+
+    private final Map<K, WeakReference<V>> map = new HashMap<>();
+
+    public void put(K key, V value) {
+        map.put(key, new WeakReference<>(value));
+    }
+
+    public V get(K key) {
+        WeakReference<V> weakReference = map.get(key);
+        return (weakReference != null) ? weakReference.get() : null;
+    }
+
+    public V remove(K key) {
+        WeakReference<V> weakReference = map.remove(key);
+        return (weakReference != null) ? weakReference.get() : null;
+    }
+
+    private void clean() {
+        map.entrySet().removeIf(entry -> entry.getValue().get() == null);
+    }
+
+}
diff --git a/src/test/java/org/traccar/handler/events/MaintenanceEventHandlerTest.java b/src/test/java/org/traccar/handler/events/MaintenanceEventHandlerTest.java
index 5320be926..661336d76 100644
--- a/src/test/java/org/traccar/handler/events/MaintenanceEventHandlerTest.java
+++ b/src/test/java/org/traccar/handler/events/MaintenanceEventHandlerTest.java
@@ -6,14 +6,15 @@ import org.traccar.model.Maintenance;
 import org.traccar.model.Position;
 import org.traccar.session.cache.CacheManager;
 
-import java.util.Arrays;
 import java.util.Date;
+import java.util.Set;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.ArgumentMatchers.anyLong;
 
 public class MaintenanceEventHandlerTest extends BaseTest {
     
@@ -29,7 +30,7 @@ public class MaintenanceEventHandlerTest extends BaseTest {
 
         var maintenance = mock(Maintenance.class);
         when(maintenance.getType()).thenReturn(Position.KEY_TOTAL_DISTANCE);
-        var maintenances = Arrays.asList(maintenance);
+        var maintenances = Set.of(maintenance);
 
         var cacheManager = mock(CacheManager.class);
         when(cacheManager.getDeviceObjects(anyLong(), eq(Maintenance.class))).thenReturn(maintenances);
@@ -48,12 +49,12 @@ public class MaintenanceEventHandlerTest extends BaseTest {
         assertTrue(eventHandler.analyzePosition(position).isEmpty());
 
         lastPosition.set(Position.KEY_TOTAL_DISTANCE, 9999);
-        position.set(Position.KEY_TOTAL_DISTANCE, 10001);        
-        assertTrue(eventHandler.analyzePosition(position).size() == 1);
+        position.set(Position.KEY_TOTAL_DISTANCE, 10001);
+        assertEquals(1, eventHandler.analyzePosition(position).size());
 
         lastPosition.set(Position.KEY_TOTAL_DISTANCE, 11999);
-        position.set(Position.KEY_TOTAL_DISTANCE, 12001);        
-        assertTrue(eventHandler.analyzePosition(position).size() == 1);
+        position.set(Position.KEY_TOTAL_DISTANCE, 12001);
+        assertEquals(1, eventHandler.analyzePosition(position).size());
         
     }