@@ -92,9 +92,6 @@ private static String nextDatabaseClientId(DatabaseId databaseId) {
 
 private final CloseableExecutorProvider asyncExecutorProvider;
 
-@GuardedBy("this")
-private final List<DatabaseClientImpl> invalidatedDbClients = new ArrayList<>();
-
 @GuardedBy("this")
 private final Map<DatabaseId, SessionClient> sessionClients = new HashMap<>();
 
@@ -204,9 +201,8 @@ public DatabaseClient getDatabaseClient(DatabaseId db) {
 checkClosed();
 String clientId = null;
 if (dbClients.containsKey(db) && !dbClients.get(db).pool.isValid()) {
-// Move the invalidated client to a separate list, so we can close it together with the
-// other database clients when the Spanner instance is closed.
-invalidatedDbClients.add(dbClients.get(db));
+// Close the invalidated client and remove it.
+dbClients.get(db).closeAsync(new ClosedException());
 clientId = dbClients.get(db).clientId;
 dbClients.remove(db);
 }
@@ -253,8 +249,7 @@ void close(long timeout, TimeUnit unit) {
 checkClosed();
 closedException = new ClosedException();
 closureFutures = new ArrayList<>();
-invalidatedDbClients.addAll(dbClients.values());
-for (DatabaseClientImpl dbClient : invalidatedDbClients) {
+for (DatabaseClientImpl dbClient : dbClients.values()) {
 closureFutures.add(dbClient.closeAsync(closedException));
 }
 dbClients.clear();