Added tracking of closed session time and expired session cleaner for clients that never reconnects but had clean session flag = false

broker/src/main/java/io/moquette/persistence/MemorySessionStore.java

@@ -25,10 +25,9 @@ import io.moquette.spi.impl.subscriptions.Topic;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.time.LocalDateTime;
 import java.util.*;
-import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.*;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.ConcurrentHashMap;
 
 public class MemorySessionStore implements ISessionsStore, ISubscriptionsStore {
 
@@ -51,6 +50,7 @@ public class MemorySessionStore implements ISessionsStore, ISubscriptionsStore {
     }
 
     private final Map<String, Session> sessions = new ConcurrentHashMap<>();
+    private ConcurrentNavigableMap<LocalDateTime, Set<String>> sessionsClosingTimes = new ConcurrentSkipListMap<>();
 
     MemorySessionStore() {
     }
@@ -280,4 +280,24 @@ public class MemorySessionStore implements ISessionsStore, ISubscriptionsStore {
         // TODO this missing last step breaks the junit test
         //sessions.remove(clientID);
     }
+
+    @Override
+    public synchronized void trackSessionClose(LocalDateTime when, String clientID) {
+        this.sessionsClosingTimes.putIfAbsent(when, new HashSet<>());
+        this.sessionsClosingTimes.computeIfPresent(when, (key, oldSet) -> {
+            oldSet.add(clientID);
+            return oldSet;
+        });
+    }
+
+    @Override
+    public Set<String> sessionOlderThan(LocalDateTime queryPin) {
+        final Set<String> results = new HashSet<>();
+        LocalDateTime keyBefore = this.sessionsClosingTimes.lowerKey(queryPin);
+        while (keyBefore != null) {
+            results.addAll(this.sessionsClosingTimes.get(keyBefore));
+            keyBefore = this.sessionsClosingTimes.lowerKey(keyBefore);
+        }
+        return results;
+    }
 }

broker/src/main/java/io/moquette/persistence/MemoryStorageService.java

@@ -28,6 +28,8 @@ public class MemoryStorageService implements IStore {
     private MemorySessionStore m_sessionsStore;
     private MemoryMessagesStore m_messagesStore;
 
+    // NB these params must be here "by contract" used in introspection instantiation used in
+    // ProtocolProcessorBootstrapper.instantiateConfiguredStore
     public MemoryStorageService(IConfig props, ScheduledExecutorService scheduler) {
         m_messagesStore = new MemoryMessagesStore();
         m_sessionsStore = new MemorySessionStore();

broker/src/main/java/io/moquette/spi/ISessionsStore.java

@@ -19,8 +19,10 @@ package io.moquette.spi;
 import io.moquette.persistence.PersistentSession;
 import io.moquette.spi.IMessagesStore.StoredMessage;
 
+import java.time.LocalDateTime;
 import java.util.Collection;
 import java.util.Queue;
+import java.util.Set;
 
 /**
  * Store used to handle the persistence of the subscriptions tree.
@@ -115,4 +117,14 @@ public interface ISessionsStore {
     int countPubReleaseWaitingPubComplete(String clientID);
 
     void removeTemporaryQoS2(String clientID);
+
+    /**
+     * Tracks the closing time of a persistent session
+     * */
+    void trackSessionClose(LocalDateTime when, String clientID);
+
+    /**
+     * List the sessions ids closed before the pin date.
+     * */
+    Set<String> sessionOlderThan(LocalDateTime queryPin);
 }

broker/src/main/java/io/moquette/spi/impl/ProtocolProcessorBootstrapper.java

@@ -97,7 +97,8 @@ public class ProtocolProcessorBootstrapper {
         store.initStore();
         messagesStore = store.messagesStore();
         m_sessionsStore = store.sessionsStore();
-        SessionsRepository sessionsRepository = new SessionsRepository(this.m_sessionsStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(this.m_sessionsStore, server.getScheduler());
+        sessionsRepository.init();
         this.subscriptionsStore = m_sessionsStore.subscriptionStore();
         storeShutdown = new Runnable() {
 

broker/src/main/java/io/moquette/spi/impl/SessionsRepository.java

@@ -13,7 +13,6 @@
  *
  * You may elect to redistribute this code under either of these licenses.
  */
-
 package io.moquette.spi.impl;
 
 import io.moquette.persistence.PersistentSession;
@@ -21,21 +20,44 @@ import io.moquette.spi.*;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.time.LocalDateTime;
+import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 
 public class SessionsRepository {
 
+    /**
+     * Task to be scheduled to execute the cleaning of persisted sessions (clean flag=false) older than a defined period.
+     */
+    private class SessionCleanerTask implements Runnable {
+
+        @Override
+        public void run() {
+            wipeExpiredSessions();
+        }
+    }
+
     private static final Logger LOG = LoggerFactory.getLogger(SessionsRepository.class);
     private final ISessionsStore sessions;
     private ISubscriptionsStore subscriptionsStore;
+    private ScheduledExecutorService scheduler;
     private final Map<String, ClientSession> sessionsCache = new ConcurrentHashMap<>();
 
-    public SessionsRepository(ISessionsStore sessionsStore) {
+    public SessionsRepository(ISessionsStore sessionsStore, ScheduledExecutorService scheduler) {
         this.sessions = sessionsStore;
         this.subscriptionsStore = sessionsStore.subscriptionStore();
+        this.scheduler = scheduler;
+    }
+
+    public void init() {
+        SessionCleanerTask cleanerTask = new SessionCleanerTask();
+        this.scheduler.schedule(cleanerTask, 1, TimeUnit.HOURS);
     }
 
     public ClientSession sessionForClient(String clientID) {
@@ -122,5 +144,15 @@ public class SessionsRepository {
         }
 
         sessionsCache.remove(clientId);
+        this.sessions.trackSessionClose(LocalDateTime.now(), clientId);
+    }
+
+    private void wipeExpiredSessions() {
+        final LocalDateTime pin = LocalDateTime.now().minus(6, ChronoUnit.DAYS);
+        final Set<String> expiredSessionsIds = this.sessions.sessionOlderThan(pin);
+        for (String expiredSession : expiredSessionsIds) {
+            this.sessions.removeDurableSession(expiredSession);
+            this.subscriptionsStore.wipeSubscriptions(expiredSession);
+        }
     }
 }

broker/src/test/java/io/moquette/spi/ClientSessionTest.java

@@ -41,7 +41,7 @@ public class ClientSessionTest {
         subscriptionsDirectory = new CTrieSubscriptionDirectory();
         MemoryStorageService storageService = new MemoryStorageService(null, null);
         ISessionsStore sessionsStore = storageService.sessionsStore();
-        sessionsRepository = new SessionsRepository(sessionsStore);
+        sessionsRepository = new SessionsRepository(sessionsStore, null);
         subscriptionsDirectory.init(sessionsRepository);
     }
 

broker/src/test/java/io/moquette/spi/impl/AbstractProtocolProcessorCommonUtils.java

@@ -68,7 +68,7 @@ abstract class AbstractProtocolProcessorCommonUtils {
         m_sessionStore = memStorage.sessionsStore();
         // m_messagesStore.initStore();
 
-        sessionsRepository = new SessionsRepository(m_sessionStore);
+        sessionsRepository = new SessionsRepository(m_sessionStore, null);
 
         Set<String> clientIds = new HashSet<>();
         clientIds.add(FAKE_CLIENT_ID);

broker/src/test/java/io/moquette/spi/impl/ProtocolProcessorTest.java

@@ -86,7 +86,7 @@ public class ProtocolProcessorTest extends AbstractProtocolProcessorCommonUtils
 
         // simulate a connect that register a clientID to an IoSession
         MemoryStorageService storageService = new MemoryStorageService(null, null);
-        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore());
+        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore(), null);
         subs.init(sessionsRepository);
         m_processor.init(subs, m_messagesStore, m_sessionStore, null, true, new PermitAllAuthorizator(),
                 NO_OBSERVERS_INTERCEPTOR, this.sessionsRepository);
@@ -123,7 +123,7 @@ public class ProtocolProcessorTest extends AbstractProtocolProcessorCommonUtils
 
         // simulate a connect that register a clientID to an IoSession
         MemoryStorageService storageService = new MemoryStorageService(null, null);
-        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore());
+        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore(), null);
         subs.init(sessionsRepository);
         m_processor.init(subs, m_messagesStore, m_sessionStore, null, true, new PermitAllAuthorizator(),
                 NO_OBSERVERS_INTERCEPTOR, this.sessionsRepository);
@@ -246,7 +246,7 @@ public class ProtocolProcessorTest extends AbstractProtocolProcessorCommonUtils
             }
         };
         MemoryStorageService storageService = new MemoryStorageService(null, null);
-        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore());
+        SessionsRepository sessionsRepository = new SessionsRepository(storageService.sessionsStore(), null);
         subs.init(sessionsRepository);
 
         // simulate a connect that register a clientID to an IoSession

broker/src/test/java/io/moquette/spi/impl/ProtocolProcessor_CONNECT_Test.java

@@ -65,11 +65,11 @@ public class ProtocolProcessor_CONNECT_Test {
         m_mockAuthenticator = new MockAuthenticator(singleton(FAKE_CLIENT_ID), singletonMap(TEST_USER, TEST_PWD));
 
         subscriptions = new CTrieSubscriptionDirectory();
-        SessionsRepository sessionsRepository = new SessionsRepository(m_sessionStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(m_sessionStore, null);
         subscriptions.init(sessionsRepository);
         m_processor = new ProtocolProcessor();
         m_processor.init(subscriptions, m_messagesStore, m_sessionStore, m_mockAuthenticator, true,
-                new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore));
+                new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore, null));
     }
 
     @Test
@@ -159,7 +159,7 @@ public class ProtocolProcessor_CONNECT_Test {
 
     protected void reinitProcessorProhibitingAnonymousClients() {
         m_processor.init(subscriptions, m_messagesStore, m_sessionStore, m_mockAuthenticator, false,
-            new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore));
+            new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore, null));
     }
 
     @Test
@@ -324,7 +324,7 @@ public class ProtocolProcessor_CONNECT_Test {
 
     protected void reinitProtocolProcessorWithZeroLengthClientIdAndAnonymousClients() {
         m_processor.init(subscriptions, m_messagesStore, m_sessionStore, m_mockAuthenticator, true, true,
-            new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore));
+            new PermitAllAuthorizator(), NO_OBSERVERS_INTERCEPTOR, new SessionsRepository(this.m_sessionStore, null));
     }
 
     @Test

broker/src/test/java/io/moquette/spi/impl/subscriptions/CTrieSubscriptionDirectoryMatchingTest.java

@@ -12,7 +12,8 @@
  * http://www.opensource.org/licenses/apache2.0.php
  *
  * You may elect to redistribute this code under either of these licenses.
- */package io.moquette.spi.impl.subscriptions;
+ */
+package io.moquette.spi.impl.subscriptions;
 
 import io.moquette.persistence.MemoryStorageService;
 import io.moquette.spi.ClientSession;
@@ -45,7 +46,7 @@ public class CTrieSubscriptionDirectoryMatchingTest {
         MemoryStorageService storageService = new MemoryStorageService(null, null);
         ISessionsStore sessionsStore = storageService.sessionsStore();
         this.subscriptionsStore = sessionsStore.subscriptionStore();
-        this.sessionsRepository = new SessionsRepository(sessionsStore);
+        this.sessionsRepository = new SessionsRepository(sessionsStore, null);
         sut.init(this.sessionsRepository);
     }
 
@@ -178,7 +179,7 @@ public class CTrieSubscriptionDirectoryMatchingTest {
         sut = new CTrieSubscriptionDirectory();
         MemoryStorageService memStore = new MemoryStorageService(null, null);
         ISessionsStore aSessionsStore = memStore.sessionsStore();
-        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore, null);
         sut.init(sessionsRepository);
 
         Subscription sub = clientSubOnTopic("AnySensor1", s);
@@ -191,7 +192,7 @@ public class CTrieSubscriptionDirectoryMatchingTest {
         sut = new CTrieSubscriptionDirectory();
         MemoryStorageService memStore = new MemoryStorageService(null, null);
         ISessionsStore aSessionsStore = memStore.sessionsStore();
-        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore, null);
         sut.init(sessionsRepository);
 
         Subscription sub = clientSubOnTopic("AnySensor1", subscription);

broker/src/test/java/io/moquette/spi/impl/subscriptions/CTrieSubscriptionDirectoryTest.java

@@ -37,7 +37,7 @@ public class CTrieSubscriptionDirectoryTest {
         sut = new CTrieSubscriptionDirectory();
         MemoryStorageService memStore = new MemoryStorageService(null, null);
         ISessionsStore aSessionsStore = memStore.sessionsStore();
-        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore, null);
         sut.init(sessionsRepository);
     }
 

h2_storage/src/main/java/io/moquette/persistence/h2/H2SessionsStore.java

@@ -27,6 +27,7 @@ import org.h2.mvstore.MVStore;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.time.LocalDateTime;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -43,6 +44,7 @@ public class H2SessionsStore implements ISessionsStore, ISubscriptionsStore {
     private Map<String, Set<Integer>> inFlightIds;
     // maps clientID->[MessageId -> guid]
     private ConcurrentMap<String, ConcurrentMap<Integer, StoredMessage>> secondPhaseStore;
+    private MVMap<LocalDateTime, Set<String>> sessionsClosingTimes;
 
     H2SessionsStore(MVStore mvStore) {
         this.mvStore = mvStore;
@@ -54,6 +56,7 @@ public class H2SessionsStore implements ISessionsStore, ISubscriptionsStore {
         this.outboundFlightMessages = mvStore.openMap("outboundFlight");
         this.inFlightIds = mvStore.openMap("inflightPacketIDs");
         this.secondPhaseStore = mvStore.openMap("secondPhase");
+        this.sessionsClosingTimes = mvStore.openMap("sessionsCreationTimes");
         LOG.info("Initialized sessions H2 store");
     }
 
@@ -290,4 +293,23 @@ public class H2SessionsStore implements ISessionsStore, ISubscriptionsStore {
         this.secondPhaseStore.remove(clientID);
     }
 
+    @Override
+    public synchronized void trackSessionClose(LocalDateTime when, String clientID) {
+        this.sessionsClosingTimes.putIfAbsent(when, new HashSet<>());
+        this.sessionsClosingTimes.computeIfPresent(when, (key, oldSet) -> {
+            oldSet.add(clientID);
+            return oldSet;
+        });
+    }
+
+    @Override
+    public Set<String> sessionOlderThan(LocalDateTime queryPin) {
+        final Set<String> results = new HashSet<>();
+        LocalDateTime keyBefore = this.sessionsClosingTimes.lowerKey(queryPin);
+        while (keyBefore != null) {
+            results.addAll(this.sessionsClosingTimes.get(keyBefore));
+            keyBefore = this.sessionsClosingTimes.lowerKey(keyBefore);
+        }
+        return results;
+    }
 }

h2_storage/src/test/java/io/moquette/persistence/h2/H2MessagesStoreTest.java

@@ -48,7 +48,7 @@ public class H2MessagesStoreTest extends MessageStoreTCK {
         storageService.initStore();
         messagesStore = storageService.messagesStore();
         sessionsStore = storageService.sessionsStore();
-        this.sessionsRepository = new SessionsRepository(sessionsStore);
+        this.sessionsRepository = new SessionsRepository(sessionsStore, null);
     }
 
     @After

h2_storage/src/test/java/io/moquette/persistence/h2/H2SessionsStoreTest.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2012-2017 The original author or authors
+ * ------------------------------------------------------
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Apache License v2.0 which accompanies this distribution.
+ *
+ * The Eclipse Public License is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * The Apache License v2.0 is available at
+ * http://www.opensource.org/licenses/apache2.0.php
+ *
+ * You may elect to redistribute this code under either of these licenses.
+ */
+package io.moquette.persistence.h2;
+
+import io.moquette.BrokerConstants;
+import io.moquette.server.config.IConfig;
+import io.moquette.server.config.MemoryConfig;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.time.LocalDateTime;
+import java.util.Properties;
+import java.util.Set;
+import java.util.concurrent.*;
+
+import static io.moquette.persistence.h2.H2MessagesStoreTest.cleanPersistenceFile;
+import static java.time.LocalDateTime.now;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class H2SessionsStoreTest {
+
+    private static final Logger LOG = LoggerFactory.getLogger(H2SessionsStoreTest.class);
+
+    private H2PersistentStore storageService;
+    private ScheduledExecutorService scheduler;
+
+    @Before
+    public void setUp() throws Exception {
+        scheduler = Executors.newScheduledThreadPool(1);
+
+        cleanPersistenceFile(BrokerConstants.DEFAULT_PERSISTENT_PATH);
+        Properties props = new Properties();
+        props.setProperty(BrokerConstants.PERSISTENT_STORE_PROPERTY_NAME, BrokerConstants.DEFAULT_PERSISTENT_PATH);
+        IConfig conf = new MemoryConfig(props);
+        storageService = new H2PersistentStore(conf, scheduler);
+        storageService.initStore();
+    }
+
+    @After
+    public void tearDown() {
+        if (storageService != null) {
+            storageService.close();
+        }
+
+        scheduler.shutdown();
+        cleanPersistenceFile(BrokerConstants.DEFAULT_PERSISTENT_PATH);
+    }
+
+    @Test
+    public void testQueryByExpirationDate() {
+        H2SessionsStore sessionsStore = (H2SessionsStore) storageService.sessionsStore();
+        LocalDateTime sessionCreationTime = LocalDateTime.of(2017, 10, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(sessionCreationTime, "Sensor1");
+
+        LocalDateTime session2CreationTime = LocalDateTime.of(2017, 11, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(session2CreationTime, "Sensor2");
+
+        //Exercise
+        LocalDateTime queryPin = LocalDateTime.of(2017, 10, 20, 10, 0, 0);
+        Set<String> sessions = sessionsStore.sessionOlderThan(queryPin);
+
+        //Verify
+        assertThat(sessions).contains("Sensor1");
+    }
+
+    @Test
+    public void testListAllSessionsOlderThan() {
+        H2SessionsStore sessionsStore = (H2SessionsStore) storageService.sessionsStore();
+        LocalDateTime sessionCreationTime = LocalDateTime.of(2017, 10, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(sessionCreationTime, "Sensor1");
+
+        LocalDateTime session2CreationTime = LocalDateTime.of(2017, 10, 2, 10, 0, 0);
+        sessionsStore.trackSessionClose(session2CreationTime, "Sensor2");
+
+        //Exercise
+        LocalDateTime queryPin = LocalDateTime.of(2017, 10, 20, 10, 0, 0);
+        Set<String> sessions = sessionsStore.sessionOlderThan(queryPin);
+
+        //Verify
+        assertThat(sessions).contains("Sensor1", "Sensor2");
+    }
+
+    @Test
+    public void testRetrieve1000ExpiredSessionPerformance() throws InterruptedException, ExecutionException, TimeoutException {
+        H2SessionsStore sessionsStore = (H2SessionsStore) storageService.sessionsStore();
+
+        final ExecutorService executorService = Executors.newFixedThreadPool(2);
+        final Future<?> future1 = executorService.submit(inserterForOffset(sessionsStore, 0));
+        final Future<?> future2 = executorService.submit(inserterForOffset(sessionsStore, 50000));
+        future1.get(2, TimeUnit.SECONDS);
+        future2.get(2, TimeUnit.SECONDS);
+//        //prepare the fixture
+//        for (int i = 0; i < 100000; i++) {
+//            final LocalDateTime timePin = now().minusSeconds(1);
+//            sessionsStore.trackSessionClose(timePin, "Sensor" + i);
+//        }
+
+        //Exercise
+        LOG.warn("Start search");
+        Set<String> sessions = sessionsStore.sessionOlderThan(now());
+        LOG.warn("Finish search");
+
+        //Verify
+        assertThat(sessions.size()).isEqualTo(100000);
+    }
+
+    private Runnable inserterForOffset(H2SessionsStore sessionsStore, int start) {
+        return () -> {
+            //prepare the fixture
+            for (int i = start; i < start + 50000; i++) {
+                final LocalDateTime timePin = now().minusSeconds(1);
+                sessionsStore.trackSessionClose(timePin, "Sensor" + i);
+            }
+        };
+    }
+}

mapdb_storage/src/main/java/io/moquette/persistence/mapdb/MapDBSessionsStore.java

@@ -26,9 +26,11 @@ import org.mapdb.DB;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.time.LocalDateTime;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ConcurrentNavigableMap;
 
 /**
  * ISessionsStore implementation backed by MapDB.
@@ -46,6 +48,7 @@ class MapDBSessionsStore implements ISessionsStore, ISubscriptionsStore {
     private ConcurrentMap<String, ConcurrentMap<Integer, StoredMessage>> m_secondPhaseStore;
 
     private final DB m_db;
+    private ConcurrentNavigableMap<LocalDateTime, Set<String>> sessionsClosingTimes;
 
     MapDBSessionsStore(DB db) {
         m_db = db;
@@ -57,6 +60,7 @@ class MapDBSessionsStore implements ISessionsStore, ISubscriptionsStore {
         m_inFlightIds = m_db.getHashMap("inflightPacketIDs");
         m_persistentSessions = m_db.getHashMap("sessions");
         m_secondPhaseStore = m_db.getHashMap("secondPhase");
+        this.sessionsClosingTimes = m_db.getTreeMap("sessionsCreationTimes");
     }
 
     @Override
@@ -291,4 +295,25 @@ class MapDBSessionsStore implements ISessionsStore, ISubscriptionsStore {
     private static String inboundMessageId2MessagesMapName(String clientID) {
         return "inboundInflight_" + clientID;
     }
+
+    @Override
+    public synchronized void trackSessionClose(LocalDateTime when, String clientID) {
+        this.sessionsClosingTimes.putIfAbsent(when, new HashSet<>());
+        this.sessionsClosingTimes.computeIfPresent(when, (key, oldSet) -> {
+            oldSet.add(clientID);
+            return oldSet;
+        });
+    }
+
+    @Override
+    public Set<String> sessionOlderThan(LocalDateTime queryPin) {
+        final Set<String> results = new HashSet<>();
+        LocalDateTime keyBefore = this.sessionsClosingTimes.lowerKey(queryPin);
+        while (keyBefore != null) {
+            results.addAll(this.sessionsClosingTimes.get(keyBefore));
+            keyBefore = this.sessionsClosingTimes.lowerKey(keyBefore);
+        }
+        return results;
+    }
+
 }

mapdb_storage/src/test/java/io/moquette/persistence/mapdb/MapDBPersistentStoreTest.java

@@ -57,7 +57,7 @@ public class MapDBPersistentStoreTest extends MessageStoreTCK {
         m_storageService.initStore();
         messagesStore = m_storageService.messagesStore();
         sessionsStore = m_storageService.sessionsStore();
-        this.sessionsRepository = new SessionsRepository(sessionsStore);
+        this.sessionsRepository = new SessionsRepository(sessionsStore, null);
     }
 
     @After
@@ -70,7 +70,7 @@ public class MapDBPersistentStoreTest extends MessageStoreTCK {
         cleanPersistenceFile(BrokerConstants.DEFAULT_PERSISTENT_PATH);
     }
 
-    public static void cleanPersistenceFile(String fileName) {
+    static void cleanPersistenceFile(String fileName) {
         File dbFile = new File(fileName);
         if (dbFile.exists()) {
             dbFile.delete();

mapdb_storage/src/test/java/io/moquette/persistence/mapdb/MapDBSessionsStoreTest.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2012-2017 The original author or authors
+ * ------------------------------------------------------
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Apache License v2.0 which accompanies this distribution.
+ *
+ * The Eclipse Public License is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * The Apache License v2.0 is available at
+ * http://www.opensource.org/licenses/apache2.0.php
+ *
+ * You may elect to redistribute this code under either of these licenses.
+ */
+package io.moquette.persistence.mapdb;
+
+import io.moquette.BrokerConstants;
+import io.moquette.server.config.IConfig;
+import io.moquette.server.config.MemoryConfig;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.time.LocalDateTime;
+import java.util.Properties;
+import java.util.Set;
+import java.util.concurrent.*;
+
+import static io.moquette.persistence.mapdb.MapDBPersistentStoreTest.cleanPersistenceFile;
+import static java.time.LocalDateTime.now;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class MapDBSessionsStoreTest {
+
+    private static final Logger LOG = LoggerFactory.getLogger(MapDBSessionsStoreTest.class);
+
+    MapDBPersistentStore storageService;
+
+    private ScheduledExecutorService scheduler;
+
+    @Before
+    public void setUp() throws Exception {
+        scheduler = Executors.newScheduledThreadPool(1);
+
+        cleanPersistenceFile(BrokerConstants.DEFAULT_PERSISTENT_PATH);
+        Properties props = new Properties();
+        props.setProperty(BrokerConstants.PERSISTENT_STORE_PROPERTY_NAME, BrokerConstants.DEFAULT_PERSISTENT_PATH);
+        IConfig conf = new MemoryConfig(props);
+        storageService = new MapDBPersistentStore(conf, scheduler);
+        storageService.initStore();
+    }
+
+    @After
+    public void tearDown() {
+        if (storageService != null) {
+            storageService.close();
+        }
+
+        scheduler.shutdown();
+        cleanPersistenceFile(BrokerConstants.DEFAULT_PERSISTENT_PATH);
+    }
+
+    @Test
+    public void testQueryByExpirationDate() {
+        MapDBSessionsStore sessionsStore = (MapDBSessionsStore) storageService.sessionsStore();
+        LocalDateTime sessionCreationTime = LocalDateTime.of(2017, 10, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(sessionCreationTime, "Sensor1");
+
+        LocalDateTime session2CreationTime = LocalDateTime.of(2017, 11, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(session2CreationTime, "Sensor2");
+
+        //Exercise
+        LocalDateTime queryPin = LocalDateTime.of(2017, 10, 20, 10, 0, 0);
+        Set<String> sessions = sessionsStore.sessionOlderThan(queryPin);
+
+        //Verify
+        assertThat(sessions).contains("Sensor1");
+    }
+
+    @Test
+    public void testListAllSessionsOlderThan() {
+        MapDBSessionsStore sessionsStore = (MapDBSessionsStore) storageService.sessionsStore();
+        LocalDateTime sessionCreationTime = LocalDateTime.of(2017, 10, 1, 10, 0, 0);
+        sessionsStore.trackSessionClose(sessionCreationTime, "Sensor1");
+
+        LocalDateTime session2CreationTime = LocalDateTime.of(2017, 10, 2, 10, 0, 0);
+        sessionsStore.trackSessionClose(session2CreationTime, "Sensor2");
+
+        //Exercise
+        LocalDateTime queryPin = LocalDateTime.of(2017, 10, 20, 10, 0, 0);
+        Set<String> sessions = sessionsStore.sessionOlderThan(queryPin);
+
+        //Verify
+        assertThat(sessions).contains("Sensor1", "Sensor2");
+    }
+
+    @Test
+    public void testRetrieve1000ExpiredSessionPerformance() throws InterruptedException, ExecutionException, TimeoutException {
+        MapDBSessionsStore sessionsStore = (MapDBSessionsStore) storageService.sessionsStore();
+
+        final ExecutorService executorService = Executors.newFixedThreadPool(2);
+        final Future<?> future1 = executorService.submit(inserterForOffset(sessionsStore, 0));
+        final Future<?> future2 = executorService.submit(inserterForOffset(sessionsStore, 5000));
+        future1.get(10, TimeUnit.SECONDS);
+        future2.get(10, TimeUnit.SECONDS);
+        //prepare the fixture
+//        for (int i = 0; i < 100000; i++) {
+//            final LocalDateTime timePin = now().minusSeconds(1);
+//            sessionsStore.trackSessionClose(timePin, "Sensor" + i);
+//        }
+
+        //Exercise
+        LOG.warn("Start search");
+        Set<String> sessions = sessionsStore.sessionOlderThan(now());
+        LOG.warn("Finish search");
+
+        //Verify
+        assertThat(sessions.size()).isEqualTo(10000);
+    }
+
+    private Runnable inserterForOffset(MapDBSessionsStore sessionsStore, int start) {
+        return () -> {
+            //prepare the fixture
+            for (int i = start; i < start + 5000; i++) {
+                final LocalDateTime timePin = now().minusSeconds(1);
+                sessionsStore.trackSessionClose(timePin, "Sensor" + i);
+            }
+        };
+    }
+
+}

perf/src/main/java/io/moquette/spi/impl/subscriptions/PerformanceTest.java

@@ -38,7 +38,7 @@ public final class PerformanceTest {
         ISubscriptionsDirectory store = new CTrieSubscriptionDirectory();
         MemoryStorageService memStore = new MemoryStorageService(null, null);
         ISessionsStore aSessionsStore = memStore.sessionsStore();
-        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore);
+        SessionsRepository sessionsRepository = new SessionsRepository(aSessionsStore, null);
         store.init(sessionsRepository);
 
         int times = 10000;