Exemple #1
// TestSetPriority verifies that the batch UserPriority is correctly set
// depending on the transaction priority.
func TestSetPriority(t *testing.T) {
	defer leaktest.AfterTest(t)()

	var expected roachpb.UserPriority

	db := NewDB(newTestSender(
		func(ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
			if ba.UserPriority != expected {
				pErr := roachpb.NewErrorf("Priority not set correctly in the batch! "+
					"(expected: %s, value: %s)", expected, ba.UserPriority)
				return nil, pErr

			br := &roachpb.BatchResponse{}
			br.Txn = &roachpb.Transaction{}
			br.Txn.Update(ba.Txn) // copy
			return br, nil
		}, nil))

	// Verify the normal priority setting path.
	expected = roachpb.HighUserPriority
	txn := NewTxn(context.Background(), *db)
	if err := txn.SetUserPriority(expected); err != nil {
	if _, pErr := txn.sendInternal(roachpb.BatchRequest{}); pErr != nil {

	// Verify the internal (fixed value) priority setting path.
	expected = roachpb.UserPriority(-13)
	txn = NewTxn(context.Background(), *db)
	if _, pErr := txn.sendInternal(roachpb.BatchRequest{}); pErr != nil {
// TestTxnPutOutOfOrder tests a case where a put operation of an older
// timestamp comes after a put operation of a newer timestamp in a
// txn. The test ensures such an out-of-order put succeeds and
// overrides an old value. The test uses a "Writer" and a "Reader"
// to reproduce an out-of-order put.
// 1) The Writer executes a put operation and writes a write intent with
//    time T in a txn.
// 2) Before the Writer's txn is committed, the Reader sends a high priority
//    get operation with time T+100. This pushes the Writer txn timestamp to
//    T+100 and triggers the restart of the Writer's txn. The original
//    write intent timestamp is also updated to T+100.
// 3) The Writer starts a new epoch of the txn, but before it writes, the
//    Reader sends another high priority get operation with time T+200. This
//    pushes the Writer txn timestamp to T+200 to trigger a restart of the
//    Writer txn. The Writer will not actually restart until it tries to commit
//    the current epoch of the transaction. The Reader updates the timestamp of
//    the write intent to T+200. The test deliberately fails the Reader get
//    operation, and cockroach doesn't update its read timestamp cache.
// 4) The Writer executes the put operation again. This put operation comes
//    out-of-order since its timestamp is T+100, while the intent timestamp
//    updated at Step 3 is T+200.
// 5) The put operation overrides the old value using timestamp T+100.
// 6) When the Writer attempts to commit its txn, the txn will be restarted
//    again at a new epoch timestamp T+200, which will finally succeed.
func TestTxnPutOutOfOrder(t *testing.T) {
	defer leaktest.AfterTest(t)()

	const key = "key"
	// Set up a filter to so that the get operation at Step 3 will return an error.
	var numGets int32

	stopper := stop.NewStopper()
	defer stopper.Stop()
	manual := hlc.NewManualClock(123)
	cfg := storage.TestStoreConfig(hlc.NewClock(manual.UnixNano, time.Nanosecond))
	cfg.TestingKnobs.TestingCommandFilter =
		func(filterArgs storagebase.FilterArgs) *roachpb.Error {
			if _, ok := filterArgs.Req.(*roachpb.GetRequest); ok &&
				filterArgs.Req.Header().Key.Equal(roachpb.Key(key)) &&
				filterArgs.Hdr.Txn == nil {
				// The Reader executes two get operations, each of which triggers two get requests
				// (the first request fails and triggers txn push, and then the second request
				// succeeds). Returns an error for the fourth get request to avoid timestamp cache
				// update after the third get operation pushes the txn timestamp.
				if atomic.AddInt32(&numGets, 1) == 4 {
					return roachpb.NewErrorWithTxn(errors.Errorf("Test"), filterArgs.Hdr.Txn)
			return nil
	eng := engine.NewInMem(roachpb.Attributes{}, 10<<20)
	store := createTestStoreWithEngine(t,

	// Put an initial value.
	initVal := []byte("initVal")
	err := store.DB().Put(context.TODO(), key, initVal)
	if err != nil {
		t.Fatalf("failed to put: %s", err)

	waitPut := make(chan struct{})
	waitFirstGet := make(chan struct{})
	waitTxnRestart := make(chan struct{})
	waitSecondGet := make(chan struct{})
	waitTxnComplete := make(chan struct{})

	// Start the Writer.
	go func() {
		epoch := -1
		// Start a txn that does read-after-write.
		// The txn will be restarted twice, and the out-of-order put
		// will happen in the second epoch.
		if err := store.DB().Txn(context.TODO(), func(txn *client.Txn) error {

			if epoch == 1 {
				// Wait until the second get operation is issued.

			updatedVal := []byte("updatedVal")
			if err := txn.Put(key, updatedVal); err != nil {
				return err

			// Make sure a get will return the value that was just written.
			actual, err := txn.Get(key)
			if err != nil {
				return err
			if !bytes.Equal(actual.ValueBytes(), updatedVal) {
				t.Fatalf("unexpected get result: %s", actual)

			if epoch == 0 {
				// Wait until the first get operation will push the txn timestamp.

			b := txn.NewBatch()
			return txn.CommitInBatch(b)
		}); err != nil {

		if epoch != 2 {
			t.Fatalf("unexpected number of txn retries: %d", epoch)



	// Start the Reader.

	// Advance the clock and send a get operation with higher
	// priority to trigger the txn restart.

	priority := roachpb.UserPriority(-math.MaxInt32)
	requestHeader := roachpb.Span{
		Key: roachpb.Key(key),
	if _, err := client.SendWrappedWith(context.Background(), rg1(store), roachpb.Header{
		Timestamp:    cfg.Clock.Now(),
		UserPriority: priority,
	}, &roachpb.GetRequest{Span: requestHeader}); err != nil {
		t.Fatalf("failed to get: %s", err)

	// Wait until the writer restarts the txn.

	// Advance the clock and send a get operation again. This time
	// we use TestingCommandFilter so that a get operation is not
	// processed after the write intent is resolved (to prevent the
	// timestamp cache from being updated).

	if _, err := client.SendWrappedWith(context.Background(), rg1(store), roachpb.Header{
		Timestamp:    cfg.Clock.Now(),
		UserPriority: priority,
	}, &roachpb.GetRequest{Span: requestHeader}); err == nil {
		t.Fatal("unexpected success of get")

Exemple #3
// InternalSetPriority sets the transaction priority. It is intended for
// internal (testing) use only.
func (txn *Txn) InternalSetPriority(priority int32) {
	// The negative user priority is translated on the server into a positive,
	// non-randomized, priority for the transaction.
	txn.UserPriority = roachpb.UserPriority(-priority)