Golang engine.MVCCGet函数代码示例

// loadAppliedIndex returns the Raft applied index and the lease applied index.
func loadAppliedIndex(
	ctx context.Context, reader engine.Reader, rangeID roachpb.RangeID,
) (uint64, uint64, error) {
	var appliedIndex uint64
	v, _, err := engine.MVCCGet(ctx, reader, keys.RaftAppliedIndexKey(rangeID),
		hlc.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, 0, err
	}
	if v != nil {
		int64AppliedIndex, err := v.GetInt()
		if err != nil {
			return 0, 0, err
		}
		appliedIndex = uint64(int64AppliedIndex)
	}
	// TODO(tschottdorf): code duplication.
	var leaseAppliedIndex uint64
	v, _, err = engine.MVCCGet(ctx, reader, keys.LeaseAppliedIndexKey(rangeID),
		hlc.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, 0, err
	}
	if v != nil {
		int64LeaseAppliedIndex, err := v.GetInt()
		if err != nil {
			return 0, 0, err
		}
		leaseAppliedIndex = uint64(int64LeaseAppliedIndex)
	}

	return appliedIndex, leaseAppliedIndex, nil
}

// loadLastIndex retrieves the last index from storage.
func loadLastIndex(eng engine.Reader, rangeID roachpb.RangeID, isInitialized bool) (uint64, error) {
	lastIndex := uint64(0)
	v, _, err := engine.MVCCGet(context.Background(), eng,
		keys.RaftLastIndexKey(rangeID),
		roachpb.ZeroTimestamp, true /* consistent */, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		int64LastIndex, err := v.GetInt()
		if err != nil {
			return 0, err
		}
		lastIndex = uint64(int64LastIndex)
	} else {
		// The log is empty, which means we are either starting from scratch
		// or the entire log has been truncated away. raftTruncatedState
		// handles both cases.
		lastEnt, err := raftTruncatedState(eng, rangeID, isInitialized)
		if err != nil {
			return 0, err
		}
		lastIndex = lastEnt.Index
	}
	return lastIndex, nil
}

// TestRejectFutureCommand verifies that lease holders reject commands that
// would cause a large time jump.
func TestRejectFutureCommand(t *testing.T) {
	defer leaktest.AfterTest(t)()

	const maxOffset = 100 * time.Millisecond
	manual := hlc.NewManualClock(0)
	clock := hlc.NewClock(manual.UnixNano)
	clock.SetMaxOffset(maxOffset)
	mtc := multiTestContext{
		clock: clock,
	}
	mtc.Start(t, 1)
	defer mtc.Stop()

	// First do a write. The first write will advance the clock by MaxOffset
	// because of the read cache's low water mark.
	getArgs := putArgs([]byte("b"), []byte("b"))
	if _, err := client.SendWrapped(rg1(mtc.stores[0]), nil, &getArgs); err != nil {
		t.Fatal(err)
	}
	if now := clock.Now(); now.WallTime != int64(maxOffset) {
		t.Fatalf("expected clock to advance to 100ms; got %s", now)
	}
	// The logical clock has advanced past the physical clock; increment
	// the "physical" clock to catch up.
	manual.Increment(int64(maxOffset))

	startTime := manual.UnixNano()

	// Commands with a future timestamp that is within the MaxOffset
	// bound will be accepted and will cause the clock to advance.
	for i := int64(0); i < 3; i++ {
		incArgs := incrementArgs([]byte("a"), 5)
		ts := hlc.ZeroTimestamp.Add(startTime+((i+1)*30)*int64(time.Millisecond), 0)
		if _, err := client.SendWrappedWith(rg1(mtc.stores[0]), nil, roachpb.Header{Timestamp: ts}, &incArgs); err != nil {
			t.Fatal(err)
		}
	}
	if now := clock.Now(); now.WallTime != int64(190*time.Millisecond) {
		t.Fatalf("expected clock to advance to 190ms; got %s", now)
	}

	// Once the accumulated offset reaches MaxOffset, commands will be rejected.
	incArgs := incrementArgs([]byte("a"), 11)
	ts := hlc.ZeroTimestamp.Add(int64((time.Duration(startTime)+maxOffset+1)*time.Millisecond), 0)
	if _, err := client.SendWrappedWith(rg1(mtc.stores[0]), nil, roachpb.Header{Timestamp: ts}, &incArgs); err == nil {
		t.Fatalf("expected clock offset error but got nil")
	}

	// The clock remained at 190ms and the final command was not executed.
	if now := clock.Now(); now.WallTime != int64(190*time.Millisecond) {
		t.Errorf("expected clock to advance to 190ms; got %s", now)
	}
	val, _, err := engine.MVCCGet(context.Background(), mtc.engines[0], roachpb.Key("a"), clock.Now(), true, nil)
	if err != nil {
		t.Fatal(err)
	}
	if v := mustGetInt(val); v != 15 {
		t.Errorf("expected 15, got %v", v)
	}
}

// loadLastIndexLocked retrieves the last index from storage.
// loadLastIndexLocked requires that the replica lock is held.
func (r *Replica) loadLastIndexLocked() (uint64, error) {
	lastIndex := uint64(0)
	v, _, err := engine.MVCCGet(r.store.Engine(),
		keys.RaftLastIndexKey(r.RangeID),
		roachpb.ZeroTimestamp, true /* consistent */, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		int64LastIndex, err := v.GetInt()
		if err != nil {
			return 0, err
		}
		lastIndex = uint64(int64LastIndex)
	} else {
		// The log is empty, which means we are either starting from scratch
		// or the entire log has been truncated away. raftTruncatedState
		// handles both cases.
		lastEnt, err := r.raftTruncatedStateLocked()
		if err != nil {
			return 0, err
		}
		lastIndex = lastEnt.Index
	}
	return lastIndex, nil
}

func loadLastIndex(
	ctx context.Context, reader engine.Reader, rangeID roachpb.RangeID,
) (uint64, error) {
	lastIndex := uint64(0)
	v, _, err := engine.MVCCGet(ctx, reader,
		keys.RaftLastIndexKey(rangeID),
		hlc.ZeroTimestamp, true /* consistent */, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		int64LastIndex, err := v.GetInt()
		if err != nil {
			return 0, err
		}
		lastIndex = uint64(int64LastIndex)
	} else {
		// The log is empty, which means we are either starting from scratch
		// or the entire log has been truncated away.
		lastEnt, err := loadTruncatedState(ctx, reader, rangeID)
		if err != nil {
			return 0, err
		}
		lastIndex = lastEnt.Index
	}
	return lastIndex, nil
}

// Get returns the value for a specified key.
func (r *Range) Get(batch engine.Engine, args proto.GetRequest) (proto.GetResponse, []proto.Intent, error) {
	var reply proto.GetResponse

	val, intents, err := engine.MVCCGet(batch, args.Key, args.Timestamp, args.ReadConsistency == proto.CONSISTENT, args.Txn)
	reply.Value = val
	return reply, intents, err
}

// loadLastIndex retrieves the last index from storage.
func (r *Replica) loadLastIndex() (uint64, error) {
	lastIndex := uint64(0)
	v, _, err := engine.MVCCGet(r.rm.Engine(),
		keys.RaftLastIndexKey(r.Desc().RangeID),
		roachpb.ZeroTimestamp, true /* consistent */, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		var err error
		_, lastIndex, err = encoding.DecodeUint64(v.GetRawBytes())
		if err != nil {
			return 0, err
		}
	} else {
		// The log is empty, which means we are either starting from scratch
		// or the entire log has been truncated away. raftTruncatedState
		// handles both cases.
		lastEnt, err := r.raftTruncatedState()
		if err != nil {
			return 0, err
		}
		lastIndex = lastEnt.Index
	}
	return lastIndex, nil
}

func loadFrozenStatus(reader engine.Reader, rangeID roachpb.RangeID) (bool, error) {
	val, _, err := engine.MVCCGet(context.Background(), reader, keys.RangeFrozenStatusKey(rangeID),
		hlc.ZeroTimestamp, true, nil)
	if err != nil {
		return false, err
	}
	if val == nil {
		return false, nil
	}
	return val.GetBool()
}

// TestRangeCommandClockUpdate verifies that followers update their
// clocks when executing a command, even if the lease holder's clock is far
// in the future.
func TestRangeCommandClockUpdate(t *testing.T) {
	defer leaktest.AfterTest(t)()

	const numNodes = 3
	var manuals []*hlc.ManualClock
	var clocks []*hlc.Clock
	for i := 0; i < numNodes; i++ {
		manuals = append(manuals, hlc.NewManualClock(1))
		clocks = append(clocks, hlc.NewClock(manuals[i].UnixNano))
		clocks[i].SetMaxOffset(100 * time.Millisecond)
	}
	mtc := multiTestContext{
		clocks: clocks,
	}
	mtc.Start(t, numNodes)
	defer mtc.Stop()
	mtc.replicateRange(1, 1, 2)

	// Advance the lease holder's clock ahead of the followers (by more than
	// MaxOffset but less than the range lease) and execute a command.
	manuals[0].Increment(int64(500 * time.Millisecond))
	incArgs := incrementArgs([]byte("a"), 5)
	ts := clocks[0].Now()
	if _, err := client.SendWrappedWith(rg1(mtc.stores[0]), nil, roachpb.Header{Timestamp: ts}, &incArgs); err != nil {
		t.Fatal(err)
	}

	// Wait for that command to execute on all the followers.
	util.SucceedsSoon(t, func() error {
		values := []int64{}
		for _, eng := range mtc.engines {
			val, _, err := engine.MVCCGet(context.Background(), eng, roachpb.Key("a"), clocks[0].Now(), true, nil)
			if err != nil {
				return err
			}
			values = append(values, mustGetInt(val))
		}
		if !reflect.DeepEqual(values, []int64{5, 5, 5}) {
			return errors.Errorf("expected (5, 5, 5), got %v", values)
		}
		return nil
	})

	// Verify that all the followers have accepted the clock update from
	// node 0 even though it comes from outside the usual max offset.
	now := clocks[0].Now()
	for i, clock := range clocks {
		// Only compare the WallTimes: it's normal for clock 0 to be a few logical ticks ahead.
		if clock.Now().WallTime < now.WallTime {
			t.Errorf("clock %d is behind clock 0: %s vs %s", i, clock.Now(), now)
		}
	}
}

// GetSequence looks up the latest sequence number recorded for this family. On a
// cache miss, zero is returned.
func (rc *ResponseCache) GetSequence(e engine.Engine, family []byte) (int64, error) {
	if len(family) == 0 {
		return 0, errEmptyID
	}

	// Pull response from the cache and read into reply if available.
	key := keys.ResponseCacheKey(rc.rangeID, family)
	v, _, err := engine.MVCCGet(e, key, roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, err
	}
	if v == nil {
		return 0, nil
	}
	return v.GetInt()
}

// TestProgressWithDownNode verifies that a surviving quorum can make progress
// with a downed node.
func TestProgressWithDownNode(t *testing.T) {
	defer leaktest.AfterTest(t)
	mtc := startMultiTestContext(t, 3)
	defer mtc.Stop()

	rangeID := roachpb.RangeID(1)
	mtc.replicateRange(rangeID, 1, 2)

	incArgs := incrementArgs([]byte("a"), 5)
	if _, err := client.SendWrapped(rg1(mtc.stores[0]), nil, &incArgs); err != nil {
		t.Fatal(err)
	}

	// Verify that the first increment propagates to all the engines.
	verify := func(expected []int64) {
		util.SucceedsWithin(t, time.Second, func() error {
			values := []int64{}
			for _, eng := range mtc.engines {
				val, _, err := engine.MVCCGet(eng, roachpb.Key("a"), mtc.clock.Now(), true, nil)
				if err != nil {
					return err
				}
				values = append(values, mustGetInt(val))
			}
			if !reflect.DeepEqual(expected, values) {
				return util.Errorf("expected %v, got %v", expected, values)
			}
			return nil
		})
	}
	verify([]int64{5, 5, 5})

	// Stop one of the replicas and issue a new increment.
	mtc.stopStore(1)
	incArgs = incrementArgs([]byte("a"), 11)
	if _, err := client.SendWrapped(rg1(mtc.stores[0]), nil, &incArgs); err != nil {
		t.Fatal(err)
	}

	// The new increment can be seen on both live replicas.
	verify([]int64{16, 5, 16})

	// Once the downed node is restarted, it will catch up.
	mtc.restartStore(1)
	verify([]int64{16, 16, 16})
}

// loadAppliedIndex retrieves the applied index from the supplied engine.
func (r *Range) loadAppliedIndex(eng engine.Engine) (uint64, error) {
	var appliedIndex uint64
	if r.isInitialized() {
		appliedIndex = raftInitialLogIndex
	} else {
		appliedIndex = 0
	}
	v, _, err := engine.MVCCGet(eng, keys.RaftAppliedIndexKey(r.Desc().RaftID),
		proto.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		_, appliedIndex = encoding.DecodeUint64(v.Bytes)
	}
	return appliedIndex, nil
}

// loadAppliedIndex retrieves the applied index from the supplied engine.
func (r *Replica) loadAppliedIndex(eng engine.Engine) (uint64, error) {
	var appliedIndex uint64
	if r.isInitialized() {
		appliedIndex = raftInitialLogIndex
	} else {
		appliedIndex = 0
	}
	v, _, err := engine.MVCCGet(eng, keys.RaftAppliedIndexKey(r.Desc().RangeID),
		roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		var err error
		_, appliedIndex, err = encoding.DecodeUint64(v.GetRawBytes())
		if err != nil {
			return 0, err
		}
	}
	return appliedIndex, nil
}

// loadAppliedIndex retrieves the applied index from the supplied engine.
func loadAppliedIndex(eng engine.Reader, rangeID roachpb.RangeID, isInitialized bool) (uint64, error) {
	var appliedIndex uint64
	if isInitialized {
		appliedIndex = raftInitialLogIndex
	} else {
		appliedIndex = 0
	}
	v, _, err := engine.MVCCGet(context.Background(), eng, keys.RaftAppliedIndexKey(rangeID),
		roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		int64AppliedIndex, err := v.GetInt()
		if err != nil {
			return 0, err
		}
		appliedIndex = uint64(int64AppliedIndex)
	}
	return appliedIndex, nil
}

// loadAppliedIndexLocked retrieves the applied index from the supplied engine.
// loadAppliedIndexLocked requires that the replica lock is held.
func (r *Replica) loadAppliedIndexLocked(eng engine.Engine) (uint64, error) {
	var appliedIndex uint64
	if r.isInitializedLocked() {
		appliedIndex = raftInitialLogIndex
	} else {
		appliedIndex = 0
	}
	v, _, err := engine.MVCCGet(eng, keys.RaftAppliedIndexKey(r.RangeID),
		roachpb.ZeroTimestamp, true, nil)
	if err != nil {
		return 0, err
	}
	if v != nil {
		int64AppliedIndex, err := v.GetInt()
		if err != nil {
			return 0, err
		}
		appliedIndex = uint64(int64AppliedIndex)
	}
	return appliedIndex, nil
}