Golang roachpb.MakeValueFromBytes函数代码示例

// TestRocksDBCompaction verifies that a garbage collector can be
// installed on a RocksDB engine and will properly compact response
// cache and transaction entries.
func TestRocksDBCompaction(t *testing.T) {
	defer leaktest.AfterTest(t)
	stopper := stop.NewStopper()
	defer stopper.Stop()
	rocksdb := newMemRocksDB(roachpb.Attributes{Attrs: []string{"ssd"}}, testCacheSize, stopper)
	err := rocksdb.Open()
	if err != nil {
		t.Fatalf("could not create new in-memory rocksdb db instance: %v", err)
	}
	rocksdb.SetGCTimeouts(1, 2)

	cmdID := &roachpb.ClientCmdID{WallTime: 1, Random: 1}

	// Write two transaction values and two response cache values such
	// that exactly one of each should be GC'd based on our GC timeouts.
	kvs := []roachpb.KeyValue{
		{
			Key:   keys.ResponseCacheKey(1, cmdID),
			Value: roachpb.MakeValueFromBytes(encodePutResponse(makeTS(2, 0), t)),
		},
		{
			Key:   keys.ResponseCacheKey(2, cmdID),
			Value: roachpb.MakeValueFromBytes(encodePutResponse(makeTS(3, 0), t)),
		},
		{
			Key:   keys.TransactionKey(roachpb.Key("a"), roachpb.Key(uuid.NewUUID4())),
			Value: roachpb.MakeValueFromBytes(encodeTransaction(makeTS(1, 0), t)),
		},
		{
			Key:   keys.TransactionKey(roachpb.Key("b"), roachpb.Key(uuid.NewUUID4())),
			Value: roachpb.MakeValueFromBytes(encodeTransaction(makeTS(2, 0), t)),
		},
	}
	for _, kv := range kvs {
		if err := MVCCPut(rocksdb, nil, kv.Key, roachpb.ZeroTimestamp, kv.Value, nil); err != nil {
			t.Fatal(err)
		}
	}

	// Compact range and scan remaining values to compare.
	rocksdb.CompactRange(nil, nil)
	actualKVs, _, err := MVCCScan(rocksdb, keyMin, keyMax, 0, roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		t.Fatalf("could not run scan: %v", err)
	}
	var keys []roachpb.Key
	for _, kv := range actualKVs {
		keys = append(keys, kv.Key)
	}
	expKeys := []roachpb.Key{
		kvs[1].Key,
		kvs[3].Key,
	}
	if !reflect.DeepEqual(expKeys, keys) {
		t.Errorf("expected keys %+v, got keys %+v", expKeys, keys)
	}
}

func runMVCCConditionalPut(valueSize int, createFirst bool, b *testing.B) {
	rng, _ := randutil.NewPseudoRand()
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueSize))
	keyBuf := append(make([]byte, 0, 64), []byte("key-")...)

	stopper := stop.NewStopper()
	defer stopper.Stop()
	rocksdb := NewInMem(roachpb.Attributes{}, testCacheSize, stopper)

	b.SetBytes(int64(valueSize))
	var expected *roachpb.Value
	if createFirst {
		for i := 0; i < b.N; i++ {
			key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(i)))
			ts := makeTS(timeutil.Now().UnixNano(), 0)
			if err := MVCCPut(rocksdb, nil, key, ts, value, nil); err != nil {
				b.Fatalf("failed put: %s", err)
			}
		}
		expected = &value
	}

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(i)))
		ts := makeTS(timeutil.Now().UnixNano(), 0)
		if err := MVCCConditionalPut(rocksdb, nil, key, ts, value, expected, nil); err != nil {
			b.Fatalf("failed put: %s", err)
		}
	}

	b.StopTimer()
}

func BenchmarkMVCCPutDelete(b *testing.B) {
	const cacheSize = 1 << 30 // 1 GB

	stopper := stop.NewStopper()
	rocksdb := NewInMem(roachpb.Attributes{}, cacheSize, stopper)
	defer stopper.Stop()

	r := rand.New(rand.NewSource(int64(timeutil.Now().UnixNano())))
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(r, 10))
	zeroTS := roachpb.ZeroTimestamp
	var blockNum int64

	for i := 0; i < b.N; i++ {
		blockID := r.Int63()
		blockNum++
		key := encoding.EncodeVarintAscending(nil, blockID)
		key = encoding.EncodeVarintAscending(key, blockNum)

		if err := MVCCPut(rocksdb, nil, key, zeroTS, value, nil /* txn */); err != nil {
			b.Fatal(err)
		}
		if err := MVCCDelete(rocksdb, nil, key, zeroTS, nil /* txn */); err != nil {
			b.Fatal(err)
		}
	}
}

func runMVCCConditionalPut(emk engineMaker, valueSize int, createFirst bool, b *testing.B) {
	rng, _ := randutil.NewPseudoRand()
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueSize))
	keyBuf := append(make([]byte, 0, 64), []byte("key-")...)

	eng, stopper := emk(b, fmt.Sprintf("cput_%d", valueSize))
	defer stopper.Stop()

	b.SetBytes(int64(valueSize))
	var expected *roachpb.Value
	if createFirst {
		for i := 0; i < b.N; i++ {
			key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(i)))
			ts := makeTS(timeutil.Now().UnixNano(), 0)
			if err := MVCCPut(context.Background(), eng, nil, key, ts, value, nil); err != nil {
				b.Fatalf("failed put: %s", err)
			}
		}
		expected = &value
	}

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(i)))
		ts := makeTS(timeutil.Now().UnixNano(), 0)
		if err := MVCCConditionalPut(context.Background(), eng, nil, key, ts, value, expected, nil); err != nil {
			b.Fatalf("failed put: %s", err)
		}
	}

	b.StopTimer()
}

// TestMultiRangeScanWithMaxResults tests that commands which access multiple
// ranges with MaxResults parameter are carried out properly.
func TestMultiRangeScanWithMaxResults(t *testing.T) {
	defer leaktest.AfterTest(t)()
	testCases := []struct {
		splitKeys []roachpb.Key
		keys      []roachpb.Key
	}{
		{[]roachpb.Key{roachpb.Key("m")},
			[]roachpb.Key{roachpb.Key("a"), roachpb.Key("z")}},
		{[]roachpb.Key{roachpb.Key("h"), roachpb.Key("q")},
			[]roachpb.Key{roachpb.Key("b"), roachpb.Key("f"), roachpb.Key("k"),
				roachpb.Key("r"), roachpb.Key("w"), roachpb.Key("y")}},
	}

	for i, tc := range testCases {
		s, _, _ := serverutils.StartServer(t, base.TestServerArgs{})
		defer s.Stopper().Stop()
		ts := s.(*TestServer)
		retryOpts := base.DefaultRetryOptions()
		retryOpts.Closer = ts.stopper.ShouldDrain()
		ds := kv.NewDistSender(&kv.DistSenderContext{
			Clock:           s.Clock(),
			RPCContext:      s.RPCContext(),
			RPCRetryOptions: &retryOpts,
		}, ts.Gossip())
		tds := kv.NewTxnCoordSender(ds, ts.Clock(), ts.Ctx.Linearizable, tracing.NewTracer(),
			ts.stopper, kv.NewTxnMetrics(metric.NewRegistry()))

		for _, sk := range tc.splitKeys {
			if err := ts.node.ctx.DB.AdminSplit(sk); err != nil {
				t.Fatal(err)
			}
		}

		for _, k := range tc.keys {
			put := roachpb.NewPut(k, roachpb.MakeValueFromBytes(k))
			if _, err := client.SendWrapped(tds, nil, put); err != nil {
				t.Fatal(err)
			}
		}

		// Try every possible ScanRequest startKey.
		for start := 0; start < len(tc.keys); start++ {
			// Try every possible maxResults, from 1 to beyond the size of key array.
			for maxResults := 1; maxResults <= len(tc.keys)-start+1; maxResults++ {
				scan := roachpb.NewScan(tc.keys[start], tc.keys[len(tc.keys)-1].Next(),
					int64(maxResults))
				reply, err := client.SendWrapped(tds, nil, scan)
				if err != nil {
					t.Fatal(err)
				}
				rows := reply.(*roachpb.ScanResponse).Rows
				if start+maxResults <= len(tc.keys) && len(rows) != maxResults {
					t.Errorf("%d: start=%s: expected %d rows, but got %d", i, tc.keys[start], maxResults, len(rows))
				} else if start+maxResults == len(tc.keys)+1 && len(rows) != maxResults-1 {
					t.Errorf("%d: expected %d rows, but got %d", i, maxResults-1, len(rows))
				}
			}
		}
	}
}

// setAppliedIndex persists a new applied index.
func setAppliedIndex(eng engine.Engine, rangeID roachpb.RangeID, appliedIndex uint64) error {
	return engine.MVCCPut(eng, nil, /* stats */
		keys.RaftAppliedIndexKey(rangeID),
		roachpb.ZeroTimestamp,
		roachpb.MakeValueFromBytes(encoding.EncodeUint64(nil, appliedIndex)),
		nil /* txn */)
}

func BenchmarkMVCCPutDelete_RocksDB(b *testing.B) {
	const cacheSize = 1 << 30 // 1 GB

	rocksdb, stopper := setupMVCCInMemRocksDB(b, "put_delete")
	defer stopper.Stop()

	r := rand.New(rand.NewSource(int64(timeutil.Now().UnixNano())))
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(r, 10))
	zeroTS := roachpb.ZeroTimestamp
	var blockNum int64

	for i := 0; i < b.N; i++ {
		blockID := r.Int63()
		blockNum++
		key := encoding.EncodeVarintAscending(nil, blockID)
		key = encoding.EncodeVarintAscending(key, blockNum)

		if err := MVCCPut(context.Background(), rocksdb, nil, key, zeroTS, value, nil /* txn */); err != nil {
			b.Fatal(err)
		}
		if err := MVCCDelete(context.Background(), rocksdb, nil, key, zeroTS, nil /* txn */); err != nil {
			b.Fatal(err)
		}
	}
}

// createPutRequest returns a ready-made request using the
// specified key, value & txn ID.
func createPutRequest(key roachpb.Key, value []byte, txn *roachpb.Transaction) (*roachpb.PutRequest, roachpb.Header) {
	h := roachpb.Header{}
	h.Txn = txn
	return &roachpb.PutRequest{
		Span: roachpb.Span{
			Key: key,
		},
		Value: roachpb.MakeValueFromBytes(value),
	}, h
}

// TestRocksDBCompaction verifies that a garbage collector can be
// installed on a RocksDB engine and will properly compact transaction
// entries.
func TestRocksDBCompaction(t *testing.T) {
	defer leaktest.AfterTest(t)
	stopper := stop.NewStopper()
	defer stopper.Stop()
	rocksdb := NewInMem(roachpb.Attributes{}, testCacheSize, stopper)
	rocksdb.SetGCTimeouts(1)

	// Write two transaction values such that exactly one should be GC'd based
	// on our GC timeouts.
	kvs := []roachpb.KeyValue{
		{
			Key:   keys.TransactionKey(roachpb.Key("a"), roachpb.Key(uuid.NewUUID4())),
			Value: roachpb.MakeValueFromBytes(encodeTransaction(makeTS(1, 0), t)),
		},
		{
			Key:   keys.TransactionKey(roachpb.Key("b"), roachpb.Key(uuid.NewUUID4())),
			Value: roachpb.MakeValueFromBytes(encodeTransaction(makeTS(2, 0), t)),
		},
	}
	for _, kv := range kvs {
		if err := MVCCPut(rocksdb, nil, kv.Key, roachpb.ZeroTimestamp, kv.Value, nil); err != nil {
			t.Fatal(err)
		}
	}

	// Compact range and scan remaining values to compare.
	rocksdb.CompactRange(NilKey, NilKey)
	actualKVs, _, err := MVCCScan(rocksdb, keyMin, keyMax, 0, roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		t.Fatalf("could not run scan: %v", err)
	}
	var keys []roachpb.Key
	for _, kv := range actualKVs {
		keys = append(keys, kv.Key)
	}
	expKeys := []roachpb.Key{
		kvs[1].Key,
	}
	if !reflect.DeepEqual(expKeys, keys) {
		t.Errorf("expected keys %+v, got keys %+v", expKeys, keys)
	}
}

// setupMVCCData writes up to numVersions values at each of numKeys
// keys. The number of versions written for each key is chosen
// randomly according to a uniform distribution. Each successive
// version is written starting at 5ns and then in 5ns increments. This
// allows scans at various times, starting at t=5ns, and continuing to
// t=5ns*(numVersions+1). A version for each key will be read on every
// such scan, but the dynamics of the scan will change depending on
// the historical timestamp. Earlier timestamps mean scans which must
// skip more historical versions; later timestamps mean scans which
// skip fewer.
//
// The creation of the rocksdb database is time consuming, especially
// for larger numbers of versions. The database is persisted between
// runs and stored in the current directory as
// "mvcc_scan_<versions>_<keys>_<valueBytes>".
func setupMVCCScanData(numVersions, numKeys, valueBytes int, b *testing.B) (*RocksDB, *stop.Stopper) {
	loc := fmt.Sprintf("mvcc_scan_%d_%d_%d", numVersions, numKeys, valueBytes)

	exists := true
	if _, err := os.Stat(loc); os.IsNotExist(err) {
		exists = false
	}

	const cacheSize = 8 << 30 // 8 GB
	stopper := stop.NewStopper()
	rocksdb := NewRocksDB(roachpb.Attributes{}, loc, cacheSize, stopper)
	if err := rocksdb.Open(); err != nil {
		b.Fatalf("could not create new rocksdb db instance at %s: %v", loc, err)
	}

	if exists {
		return rocksdb, stopper
	}

	log.Infof("creating mvcc data: %s", loc)

	rng, _ := randutil.NewPseudoRand()
	keys := make([]roachpb.Key, numKeys)
	nvs := make([]int, numKeys)
	for t := 1; t <= numVersions; t++ {
		walltime := int64(5 * t)
		ts := makeTS(walltime, 0)
		batch := rocksdb.NewBatch()
		for i := 0; i < numKeys; i++ {
			if t == 1 {
				keys[i] = roachpb.Key(encoding.EncodeUvarint([]byte("key-"), uint64(i)))
				nvs[i] = rand.Intn(numVersions) + 1
			}
			// Only write values if this iteration is less than the random
			// number of versions chosen for this key.
			if t <= nvs[i] {
				value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueBytes))
				value.InitChecksum(keys[i])
				if err := MVCCPut(batch, nil, keys[i], ts, value, nil); err != nil {
					b.Fatal(err)
				}
			}
		}
		if err := batch.Commit(); err != nil {
			b.Fatal(err)
		}
		batch.Close()
	}
	rocksdb.CompactRange(nil, nil)

	return rocksdb, stopper
}

func runMVCCPut(valueSize int, b *testing.B) {
	rng, _ := randutil.NewPseudoRand()
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueSize))
	keyBuf := append(make([]byte, 0, 64), []byte("key-")...)

	stopper := stop.NewStopper()
	defer stopper.Stop()
	rocksdb := NewInMem(roachpb.Attributes{Attrs: []string{"ssd"}}, testCacheSize, stopper)

	b.SetBytes(int64(valueSize))
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		key := roachpb.Key(encoding.EncodeUvarint(keyBuf[0:4], uint64(i)))
		ts := makeTS(time.Now().UnixNano(), 0)
		if err := MVCCPut(rocksdb, nil, key, ts, value, nil); err != nil {
			b.Fatalf("failed put: %s", err)
		}
	}

	b.StopTimer()
}

func runMVCCBatchPut(valueSize, batchSize int, b *testing.B) {
	defer tracing.Disable()()
	rng, _ := randutil.NewPseudoRand()
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueSize))
	keyBuf := append(make([]byte, 0, 64), []byte("key-")...)

	stopper := stop.NewStopper()
	defer stopper.Stop()
	rocksdb := NewInMem(roachpb.Attributes{}, testCacheSize, stopper)

	b.SetBytes(int64(valueSize))
	b.ResetTimer()

	for i := 0; i < b.N; i += batchSize {
		end := i + batchSize
		if end > b.N {
			end = b.N
		}

		batch := rocksdb.NewBatch()

		for j := i; j < end; j++ {
			key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(j)))
			ts := makeTS(time.Now().UnixNano(), 0)
			if err := MVCCPut(batch, nil, key, ts, value, nil); err != nil {
				b.Fatalf("failed put: %s", err)
			}
		}

		if err := batch.Commit(); err != nil {
			b.Fatal(err)
		}

		batch.Close()
	}

	b.StopTimer()
}

func runMVCCBatchPut(emk engineMaker, valueSize, batchSize int, b *testing.B) {
	rng, _ := randutil.NewPseudoRand()
	value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueSize))
	keyBuf := append(make([]byte, 0, 64), []byte("key-")...)

	stopper := stop.NewStopper()
	eng, stopper := emk(b, fmt.Sprintf("batch_put_%d_%d", valueSize, batchSize))
	defer stopper.Stop()

	b.SetBytes(int64(valueSize))
	b.ResetTimer()

	for i := 0; i < b.N; i += batchSize {
		end := i + batchSize
		if end > b.N {
			end = b.N
		}

		batch := eng.NewBatch()

		for j := i; j < end; j++ {
			key := roachpb.Key(encoding.EncodeUvarintAscending(keyBuf[:4], uint64(j)))
			ts := makeTS(timeutil.Now().UnixNano(), 0)
			if err := MVCCPut(context.Background(), batch, nil, key, ts, value, nil); err != nil {
				b.Fatalf("failed put: %s", err)
			}
		}

		if err := batch.Commit(); err != nil {
			b.Fatal(err)
		}

		batch.Close()
	}

	b.StopTimer()
}

// setupMVCCData writes up to numVersions values at each of numKeys
// keys. The number of versions written for each key is chosen
// randomly according to a uniform distribution. Each successive
// version is written starting at 5ns and then in 5ns increments. This
// allows scans at various times, starting at t=5ns, and continuing to
// t=5ns*(numVersions+1). A version for each key will be read on every
// such scan, but the dynamics of the scan will change depending on
// the historical timestamp. Earlier timestamps mean scans which must
// skip more historical versions; later timestamps mean scans which
// skip fewer.
//
// The creation of the rocksdb database is time consuming, especially
// for larger numbers of versions. The database is persisted between
// runs and stored in the current directory as
// "mvcc_scan_<versions>_<keys>_<valueBytes>".
func setupMVCCData(numVersions, numKeys, valueBytes int, b *testing.B) (*RocksDB, *stop.Stopper) {
	loc := fmt.Sprintf("mvcc_data_%d_%d_%d", numVersions, numKeys, valueBytes)

	exists := true
	if _, err := os.Stat(loc); os.IsNotExist(err) {
		exists = false
	}

	const cacheSize = 0
	const memtableBudget = 512 << 20 // 512 MB
	stopper := stop.NewStopper()
	rocksdb := NewRocksDB(roachpb.Attributes{}, loc, cacheSize, memtableBudget, stopper)
	if err := rocksdb.Open(); err != nil {
		b.Fatalf("could not create new rocksdb db instance at %s: %v", loc, err)
	}

	if exists {
		readAllFiles(filepath.Join(loc, "*"))
		return rocksdb, stopper
	}

	log.Infof("creating mvcc data: %s", loc)

	// Generate the same data every time.
	rng := rand.New(rand.NewSource(1449168817))

	keys := make([]roachpb.Key, numKeys)
	var order []int
	for i := 0; i < numKeys; i++ {
		keys[i] = roachpb.Key(encoding.EncodeUvarint([]byte("key-"), uint64(i)))
		keyVersions := rng.Intn(numVersions) + 1
		for j := 0; j < keyVersions; j++ {
			order = append(order, i)
		}
	}

	// Randomize the order in which the keys are written.
	for i, n := 0, len(order)-2; i < n; i++ {
		j := i + rng.Intn(n-i)
		order[i], order[j] = order[j], order[i]
	}

	counts := make([]int, numKeys)
	batch := rocksdb.NewBatch()
	for i, idx := range order {
		// Output the keys in ~20 batches. If we used a single batch to output all
		// of the keys rocksdb would create a single sstable. We want multiple
		// sstables in order to exercise filtering of which sstables are examined
		// during iterator seeking. We fix the number of batches we output so that
		// optimizations which change the data size result in the same number of
		// sstables.
		if i > 0 && (i%(len(order)/20)) == 0 {
			if err := batch.Commit(); err != nil {
				b.Fatal(err)
			}
			batch.Close()
			batch = rocksdb.NewBatch()
			if err := rocksdb.Flush(); err != nil {
				b.Fatal(err)
			}
		}

		key := keys[idx]
		ts := makeTS(int64(counts[idx]+1)*5, 0)
		counts[idx]++
		value := roachpb.MakeValueFromBytes(randutil.RandBytes(rng, valueBytes))
		value.InitChecksum(key)
		if err := MVCCPut(batch, nil, key, ts, value, nil); err != nil {
			b.Fatal(err)
		}
	}
	if err := batch.Commit(); err != nil {
		b.Fatal(err)
	}
	batch.Close()
	if err := rocksdb.Flush(); err != nil {
		b.Fatal(err)
	}

	return rocksdb, stopper
}

// TestMultiRangeScanDeleteRange tests that commands which access multiple
// ranges are carried out properly.
func TestMultiRangeScanDeleteRange(t *testing.T) {
	defer leaktest.AfterTest(t)
	s := StartTestServer(t)
	defer s.Stop()
	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: s.Clock()}, s.Gossip())
	tds := kv.NewTxnCoordSender(ds, s.Clock(), testContext.Linearizable, nil, s.stopper)

	if err := s.node.ctx.DB.AdminSplit("m"); err != nil {
		t.Fatal(err)
	}
	writes := []roachpb.Key{roachpb.Key("a"), roachpb.Key("z")}
	get := &roachpb.GetRequest{
		Span: roachpb.Span{Key: writes[0]},
	}
	get.EndKey = writes[len(writes)-1]
	if _, err := client.SendWrapped(tds, nil, get); err == nil {
		t.Errorf("able to call Get with a key range: %v", get)
	}
	var delTS roachpb.Timestamp
	for i, k := range writes {
		put := roachpb.NewPut(k, roachpb.MakeValueFromBytes(k))
		reply, err := client.SendWrapped(tds, nil, put)
		if err != nil {
			t.Fatal(err)
		}
		scan := roachpb.NewScan(writes[0], writes[len(writes)-1].Next(), 0).(*roachpb.ScanRequest)
		// The Put ts may have been pushed by tsCache,
		// so make sure we see their values in our Scan.
		delTS = reply.(*roachpb.PutResponse).Timestamp
		reply, err = client.SendWrappedWith(tds, nil, roachpb.Header{Timestamp: delTS}, scan)
		if err != nil {
			t.Fatal(err)
		}
		sr := reply.(*roachpb.ScanResponse)
		if sr.Txn != nil {
			// This was the other way around at some point in the past.
			// Same below for Delete, etc.
			t.Errorf("expected no transaction in response header")
		}
		if rows := sr.Rows; len(rows) != i+1 {
			t.Fatalf("expected %d rows, but got %d", i+1, len(rows))
		}
	}

	del := &roachpb.DeleteRangeRequest{
		Span: roachpb.Span{
			Key:    writes[0],
			EndKey: roachpb.Key(writes[len(writes)-1]).Next(),
		},
	}
	reply, err := client.SendWrappedWith(tds, nil, roachpb.Header{Timestamp: delTS}, del)
	if err != nil {
		t.Fatal(err)
	}
	dr := reply.(*roachpb.DeleteRangeResponse)
	if dr.Txn != nil {
		t.Errorf("expected no transaction in response header")
	}
	if n := dr.NumDeleted; n != int64(len(writes)) {
		t.Errorf("expected %d keys to be deleted, but got %d instead",
			len(writes), n)
	}

	scan := roachpb.NewScan(writes[0], writes[len(writes)-1].Next(), 0).(*roachpb.ScanRequest)
	txn := &roachpb.Transaction{Name: "MyTxn"}
	reply, err = client.SendWrappedWith(tds, nil, roachpb.Header{Txn: txn}, scan)
	if err != nil {
		t.Fatal(err)
	}
	sr := reply.(*roachpb.ScanResponse)
	if txn := sr.Txn; txn == nil || txn.Name != "MyTxn" {
		t.Errorf("wanted Txn to persist, but it changed to %v", txn)
	}
	if rows := sr.Rows; len(rows) > 0 {
		t.Fatalf("scan after delete returned rows: %v", rows)
	}
}