protected void startStorageTx(OTransaction clientTx) throws IOException {
if (writeAheadLog == null)
return;
final OStorageTransaction storageTx = transaction.get();
if (storageTx != null && storageTx.getClientTx().getId() != clientTx.getId())
rollback(clientTx);
assert atomicOperationsManager.getCurrentOperation() == null;
atomicOperationsManager.startAtomicOperation();
transaction.set(new OStorageTransaction(clientTx));
}