public int size() {
checkTransactionState();
try {
final OperationService operationService = getNodeEngine().getOperationService();
final Map<Integer, Object> results = operationService.invokeOnAllPartitions(MultiMapService.SERVICE_NAME,
new MultiMapOperationFactory(name, MultiMapOperationFactory.OperationFactoryType.SIZE));
int size = 0;
for (Object obj : results.values()) {
if (obj == null) {
continue;
}