diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseClient.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseClient.java
index 0021eb7..a6320ed 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseClient.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseClient.java
@@ -3,6 +3,7 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 
@@ -37,7 +38,7 @@
 
     public boolean createTable(String tableName, int ttlMillis) {
 
-        CompletableFuture<Boolean> future = copycat.submit("createTable", tableName, ttlMillis);
+        CompletableFuture<Boolean> future = copycat.submit("createTableWithExpiration", tableName);
         try {
             return future.get();
         } catch (InterruptedException | ExecutionException e) {
@@ -65,9 +66,9 @@
         }
     }
 
-    public List<String> listTables() {
+    public Set<String> listTables() {
 
-        CompletableFuture<List<String>> future = copycat.submit("listTables");
+        CompletableFuture<Set<String>> future = copycat.submit("listTables");
         try {
             return future.get();
         } catch (InterruptedException | ExecutionException e) {
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseEntryExpirationTracker.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseEntryExpirationTracker.java
index 157d3a6..62cf584 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseEntryExpirationTracker.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseEntryExpirationTracker.java
@@ -33,7 +33,6 @@
 import org.onlab.onos.cluster.ControllerNode;
 import org.onlab.onos.store.cluster.messaging.ClusterCommunicationService;
 import org.onlab.onos.store.cluster.messaging.ClusterMessage;
-import org.onlab.onos.store.cluster.messaging.MessageSubject;
 import org.onlab.onos.store.service.DatabaseService;
 import org.onlab.onos.store.service.VersionedValue;
 import org.onlab.onos.store.service.impl.DatabaseStateMachine.State;
@@ -51,9 +50,6 @@
 
     private final Logger log = LoggerFactory.getLogger(getClass());
 
-    public static final MessageSubject DATABASE_UPDATES = new MessageSubject(
-            "database-update-event");
-
     private final DatabaseService databaseService;
     private final ClusterCommunicationService clusterCommunicator;
 
@@ -61,9 +57,9 @@
     private final ControllerNode localNode;
     private final AtomicBoolean isLocalMemberLeader = new AtomicBoolean(false);
 
-    private final Map<String, Map<DatabaseRow, VersionedValue>> tableEntryExpirationMap = new HashMap<>();
+    private final Map<String, Map<DatabaseRow, Long>> tableEntryExpirationMap = new HashMap<>();
 
-    private final ExpirationListener<DatabaseRow, VersionedValue> expirationObserver = new ExpirationObserver();
+    private final ExpirationListener<DatabaseRow, Long> expirationObserver = new ExpirationObserver();
 
     DatabaseEntryExpirationTracker(
             Member localMember,
@@ -78,31 +74,38 @@
 
     @Override
     public void tableModified(TableModificationEvent event) {
+        log.debug("Received a table modification event {}", event);
+
         if (!tableEntryExpirationMap.containsKey(event.tableName())) {
             return;
         }
 
+        Map<DatabaseRow, Long> map = tableEntryExpirationMap.get(event.tableName());
         DatabaseRow row = new DatabaseRow(event.tableName(), event.key());
-        Map<DatabaseRow, VersionedValue> map = tableEntryExpirationMap
-                .get(event.tableName());
+        Long eventVersion = event.value().version();
 
         switch (event.type()) {
         case ROW_DELETED:
+            map.remove(row, eventVersion);
             if (isLocalMemberLeader.get()) {
                 try {
+                    // FIXME: The broadcast message should be sent to self.
                     clusterCommunicator.broadcast(new ClusterMessage(
-                            localNode.id(), DATABASE_UPDATES,
+                            localNode.id(), DatabaseStateMachine.DATABASE_UPDATE_EVENTS,
                             DatabaseStateMachine.SERIALIZER.encode(event)));
                 } catch (IOException e) {
-                    log.error(
-                            "Failed to broadcast a database table modification event.",
-                            e);
+                    log.error("Failed to broadcast a database row deleted event.", e);
                 }
             }
             break;
         case ROW_ADDED:
         case ROW_UPDATED:
-            map.put(row, null);
+            // To account for potential reordering of notifications,
+            // check to make sure we are replacing an old version with a new version
+            Long currentVersion = map.get(row);
+            if (currentVersion == null || currentVersion < eventVersion) {
+                map.put(row, eventVersion);
+            }
             break;
         default:
             break;
@@ -111,60 +114,56 @@
 
     @Override
     public void tableCreated(TableMetadata metadata) {
+        log.debug("Received a table created event {}", metadata);
         if (metadata.expireOldEntries()) {
             tableEntryExpirationMap.put(metadata.tableName(), ExpiringMap.builder()
-                    .expiration(metadata.ttlMillis(), TimeUnit.SECONDS)
+                    .expiration(metadata.ttlMillis(), TimeUnit.MILLISECONDS)
                     .expirationListener(expirationObserver)
-                    // FIXME: make the expiration policy configurable.
+                    // TODO: make the expiration policy configurable.
+                    // Do we need to support expiration based on last access time?
                     .expirationPolicy(ExpirationPolicy.CREATED).build());
         }
     }
 
     @Override
     public void tableDeleted(String tableName) {
+        log.debug("Received a table deleted event for table ({})", tableName);
         tableEntryExpirationMap.remove(tableName);
     }
 
     private class ExpirationObserver implements
-            ExpirationListener<DatabaseRow, VersionedValue> {
+            ExpirationListener<DatabaseRow, Long> {
         @Override
-        public void expired(DatabaseRow key, VersionedValue value) {
+        public void expired(DatabaseRow row, Long version) {
+            Map<DatabaseRow, Long> map = tableEntryExpirationMap.get(row.tableName);
             try {
                 if (isLocalMemberLeader.get()) {
-                    if (!databaseService.removeIfVersionMatches(key.tableName,
-                            key.key, value.version())) {
-                        log.info("Entry in the database changed before right its TTL expiration.");
+                    if (!databaseService.removeIfVersionMatches(row.tableName,
+                            row.key, version)) {
+                        log.info("Entry in database was updated right before its expiration.");
+                    } else {
+                        log.info("Successfully expired old entry with key ({}) from table ({})",
+                                row.key, row.tableName);
                     }
                 } else {
-                    // If this node is not the current leader, we should never
-                    // let the expiring entries drop off
-                    // Under stable conditions (i.e no leadership switch) the
-                    // current leader will initiate
-                    // a database remove and this instance will get notified
-                    // of a tableModification event causing it to remove from
-                    // the map.
-                    Map<DatabaseRow, VersionedValue> map = tableEntryExpirationMap
-                            .get(key.tableName);
+                    // Only the current leader will expire keys from database.
+                    // Everyone else function as standby just in case they need to take over
                     if (map != null) {
-                        map.put(key, value);
+                        map.putIfAbsent(row, version);
                     }
                 }
 
             } catch (Exception e) {
-                log.warn(
-                        "Failed to delete entry from the database after ttl expiration. Will retry eviction",
-                        e);
-                tableEntryExpirationMap.get(key.tableName).put(
-                        new DatabaseRow(key.tableName, key.key), value);
+                log.warn("Failed to delete entry from the database after ttl "
+                        + "expiration. Operation will be retried.", e);
+                map.putIfAbsent(row, version);
             }
         }
     }
 
     @Override
     public void handle(LeaderElectEvent event) {
-        if (localMember.equals(event.leader())) {
-            isLocalMemberLeader.set(true);
-        }
+        isLocalMemberLeader.set(localMember.equals(event.leader()));
     }
 
     /**
@@ -212,12 +211,12 @@
                 continue;
             }
 
-            Map<DatabaseRow, VersionedValue> tableExpirationMap = ExpiringMap.builder()
+            Map<DatabaseRow, Long> tableExpirationMap = ExpiringMap.builder()
                     .expiration(metadata.ttlMillis(), TimeUnit.MILLISECONDS)
                     .expirationListener(expirationObserver)
                     .expirationPolicy(ExpirationPolicy.CREATED).build();
             for (Map.Entry<String, VersionedValue> entry : state.getTable(tableName).entrySet()) {
-                tableExpirationMap.put(new DatabaseRow(tableName, entry.getKey()), entry.getValue());
+                tableExpirationMap.put(new DatabaseRow(tableName, entry.getKey()), entry.getValue().version());
             }
 
             tableEntryExpirationMap.put(tableName, tableExpirationMap);
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseManager.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseManager.java
index e233e5a..ad1ef853 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseManager.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseManager.java
@@ -7,7 +7,6 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
@@ -19,6 +18,7 @@
 import net.kuujo.copycat.cluster.TcpCluster;
 import net.kuujo.copycat.cluster.TcpClusterConfig;
 import net.kuujo.copycat.cluster.TcpMember;
+import net.kuujo.copycat.event.LeaderElectEvent;
 import net.kuujo.copycat.log.Log;
 
 import org.apache.felix.scr.annotations.Activate;
@@ -160,18 +160,22 @@
         }
         log.info("Starting cluster: {}", cluster);
 
+        DatabaseEntryExpirationTracker expirationTracker =
+                new DatabaseEntryExpirationTracker(
+                        clusterConfig.getLocalMember(),
+                        clusterService.getLocalNode(),
+                        clusterCommunicator,
+                        this);
 
         DatabaseStateMachine stateMachine = new DatabaseStateMachine();
-        stateMachine.addEventListener(
-                new DatabaseEntryExpirationTracker(
-                    clusterConfig.getLocalMember(),
-                    clusterService.getLocalNode(),
-                    clusterCommunicator,
-                    this));
+        stateMachine.addEventListener(expirationTracker);
         Log consensusLog = new MapDBLog(LOG_FILE_PREFIX + localNode.id(),
                                         ClusterMessagingProtocol.SERIALIZER);
 
         copycat = new Copycat(stateMachine, consensusLog, cluster, copycatMessagingProtocol);
+
+        copycat.event(LeaderElectEvent.class).registerHandler(expirationTracker);
+
         copycat.start();
 
         client = new DatabaseClient(copycat);
@@ -207,7 +211,7 @@
     }
 
     @Override
-    public List<String> listTables() {
+    public Set<String> listTables() {
         return client.listTables();
     }
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseStateMachine.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseStateMachine.java
index 3b0d874..cdf66af 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseStateMachine.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DatabaseStateMachine.java
@@ -30,6 +30,7 @@
 import org.onlab.util.KryoNamespace;
 import org.slf4j.Logger;
 
+import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
@@ -65,6 +66,7 @@
                     .register(WriteStatus.class)
                     // TODO: Move this out ?
                     .register(TableModificationEvent.class)
+                    .register(TableModificationEvent.Type.class)
                     .register(ClusterMessagingProtocol.COMMON)
                     .build()
                     .populate(1);
@@ -85,7 +87,8 @@
     }
 
     @Command
-    public boolean createTable(String tableName, int ttlMillis) {
+    public boolean createTableWithExpiration(String tableName) {
+        int ttlMillis = 10000;
         TableMetadata metadata = new TableMetadata(tableName, ttlMillis);
         return createTable(metadata);
     }
@@ -266,6 +269,7 @@
         // notify listeners of table mod events.
         for (DatabaseUpdateEventListener listener : listeners) {
             for (TableModificationEvent tableModificationEvent : tableModificationEvents) {
+                log.info("Publishing table modification event: {}", tableModificationEvent);
                 listener.tableModified(tableModificationEvent);
             }
         }
@@ -345,6 +349,15 @@
         public int ttlMillis() {
             return ttlMillis;
         }
+
+        @Override
+        public String toString() {
+            return MoreObjects.toStringHelper(getClass())
+                    .add("tableName", tableName)
+                    .add("expireOldEntries", expireOldEntries)
+                    .add("ttlMillis", ttlMillis)
+                    .toString();
+        }
     }
 
     @Override
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
index c466941..cef53a5 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
@@ -80,6 +80,7 @@
                 return false;
             }
         }
+        isLocked.set(true);
         lockExpirationTime = DateTime.now().plusMillis(leaseDurationMillis);
         return true;
     }
@@ -95,9 +96,11 @@
             if (DateTime.now().isAfter(lockExpirationTime)) {
                 isLocked.set(false);
                 return false;
+            } else {
+                return true;
             }
         }
-        return true;
+        return false;
     }
 
     @Override
@@ -105,6 +108,7 @@
         if (!isLocked()) {
             return;
         } else {
+            isLocked.set(false);
             databaseService.removeIfValueMatches(DistributedLockManager.ONOS_LOCK_TABLE_NAME, path, lockId);
         }
     }
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLockManager.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLockManager.java
index 6d99ba7..c8b16e4 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLockManager.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLockManager.java
@@ -94,6 +94,8 @@
                 return;
             }
 
+            log.info("Received a lock available event for path: {}", event.key());
+
             String path = event.key();
             if (!locksToAcquire.containsKey(path)) {
                 return;
@@ -159,4 +161,4 @@
             return future;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/TableModificationEvent.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/TableModificationEvent.java
index b0962dc..31dcaab 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/TableModificationEvent.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/TableModificationEvent.java
@@ -2,6 +2,8 @@
 
 import org.onlab.onos.store.service.VersionedValue;
 
+import com.google.common.base.MoreObjects;
+
 /**
  * A table modification event.
  */
@@ -9,7 +11,6 @@
 
     /**
      * Type of table modification event.
-     *
      */
     public enum Type {
         ROW_ADDED,
@@ -94,4 +95,14 @@
     public Type type() {
         return type;
     }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("type", type)
+                .add("tableName", tableName)
+                .add("key", key)
+                .add("version", value.version())
+                .toString();
+    }
 }