func (tc *TxnCoordSender) heartbeat(id string, trace *tracer.Trace, ctx context.Context) bool {
	proceed := true
	txnMeta := tc.txns[id]
	// Before we send a heartbeat, determine whether this transaction
	// should be considered abandoned. If so, exit heartbeat.
	if txnMeta.hasClientAbandonedCoord(tc.clock.PhysicalNow()) {
		// TODO(tschottdorf): should we be more proactive here?
		// The client might be continuing the transaction
		// through another coordinator, but in the most likely
		// case it's just gone and the open transaction record
		// could block concurrent operations.
		if log.V(1) {
			log.Infof("transaction %s abandoned; stopping heartbeat",
		proceed = false
	// txnMeta.txn is possibly replaced concurrently,
	// so grab a copy before unlocking.
	txn := txnMeta.txn
	if !proceed {
		return false

	hb := &roachpb.HeartbeatTxnRequest{}
	hb.Key = txn.Key
	ba := roachpb.BatchRequest{}
	ba.Timestamp = tc.clock.Now()
	ba.Key = txn.Key
	ba.Txn = &txn

	epochEnds := trace.Epoch("heartbeat")
	_, err := tc.wrapped.Send(ctx, ba)
	// If the transaction is not in pending state, then we can stop
	// the heartbeat. It's either aborted or committed, and we resolve
	// write intents accordingly.
	if err != nil {
		log.Warningf("heartbeat to %s failed: %s", txn, err)
	// TODO(bdarnell): once we have gotten a heartbeat response with
	// Status != PENDING, future heartbeats are useless. However, we
	// need to continue the heartbeatLoop until the client either
	// commits or abandons the transaction. We could save a little
	// pointless work by restructuring this loop to stop sending
	// heartbeats between the time that the transaction is aborted and
	// the client finds out. Furthermore, we could use this information
	// to send TransactionAbortedErrors to the client so it can restart
	// immediately instead of running until its EndTransaction.
	return true
Example #2
func TestStoreExecuteNoop(t *testing.T) {
	defer leaktest.AfterTest(t)
	store, _, stopper := createTestStore(t)
	defer stopper.Stop()
	ba := roachpb.BatchRequest{}
	ba.Key = nil // intentional
	ba.RangeID = 1
	ba.Replica = roachpb.ReplicaDescriptor{StoreID: store.StoreID()}
	ba.Add(&roachpb.GetRequest{RequestHeader: roachpb.RequestHeader{Key: roachpb.Key("a")}})

	br, pErr := store.Send(context.Background(), ba)
	if pErr != nil {
	reply := br.Responses[1].GetInner()
	if _, ok := reply.(*roachpb.NoopResponse); !ok {
		t.Errorf("expected *roachpb.NoopResponse, got %T", reply)