func raftLogKeyPrint(key roachpb.Key) string {
	var logIndex uint64
	var err error
	key, logIndex, err = encoding.DecodeUint64Ascending(key)
	if err != nil {
		return fmt.Sprintf("/err<%v:%q>", err, []byte(key))
	}

	return fmt.Sprintf("%s%d", strLogIndex, logIndex)
}

// GetFloat decodes a float64 value from the bytes field of the receiver. If
// the bytes field is not 8 bytes in length or the tag is not FLOAT an error
// will be returned.
func (v Value) GetFloat() (float64, error) {
	if tag := v.GetTag(); tag != ValueType_FLOAT {
		return 0, fmt.Errorf("value type is not %s: %s", ValueType_FLOAT, tag)
	}
	dataBytes := v.dataBytes()
	if len(dataBytes) != 8 {
		return 0, fmt.Errorf("float64 value should be exactly 8 bytes: %d", len(dataBytes))
	}
	_, u, err := encoding.DecodeUint64Ascending(dataBytes)
	if err != nil {
		return 0, err
	}
	return math.Float64frombits(u), nil
}

// DecodeFloatValue decodes a value encoded by EncodeFloatValue.
func DecodeFloatValue(b []byte) ([]byte, float64, error) {
	if len(b) == 0 {
		return nil, 0, fmt.Errorf("array is empty")
	}
	if tag := ValueType(b[0]); tag != ValueType_FLOAT {
		return nil, 0, fmt.Errorf("value type is not %s: %s", ValueType_FLOAT, tag)
	}
	b = b[1:]
	if len(b) < 8 {
		return nil, 0, fmt.Errorf("float64 value should be exactly 8 bytes: %d", len(b))
	}
	b, f, err := encoding.DecodeUint64Ascending(b)
	return b, math.Float64frombits(f), err
}

// outputDotFile generates a .dot file describing the current state of
// the gossip network. nodes is a map from network address to gossip
// node. edgeSet is empty on the first invocation, but
// its content is set to encompass the entire set of edges in the
// network when this method returns. It should be resupplied with each
// successive invocation, as it is used to determine which edges are
// new and which have been deleted and show those changes visually in
// the output graph. New edges are drawn green; edges which were
// removed over the course of the last simulation step(s) are drawn in
// a lightly-dashed red.
//
// The format of the output looks like this:
//
//   digraph G {
//   node [shape=record];
//        node1 [fontsize=12,label="{Node 1|MH=3}"]
//        node1 -> node3 [color=green]
//        node1 -> node4
//        node1 -> node5 [color=red,style=dotted]
//        node2 [fontsize=24,label="{Node 2|MH=2}"]
//        node2 -> node5
//        node3 [fontsize=18,label="{Node 3|MH=5}"]
//        node3 -> node5
//        node3 -> node4
//        node4 [fontsize=24,label="{Node 4|MH=4}"]
//        node4 -> node2
//        node5 [fontsize=24,label="{Node 5|MH=1}"]
//        node5 -> node2
//        node5 -> node3
//   }
//
// Returns the name of the output file and a boolean for whether or not
// the network has quiesced (that is, no new edges, and all nodes are
// connected).
func outputDotFile(dotFN string, cycle int, network *simulation.Network, edgeSet map[string]edge) (string, bool) {
	f, err := os.Create(dotFN)
	if err != nil {
		log.Fatalf("unable to create temp file: %s", err)
	}
	defer f.Close()

	// Determine maximum number of incoming connections. Create outgoing
	// edges, keeping track of which are new since last time (added=true).
	outgoingMap := make(edgeMap)
	var maxIncoming int
	quiescent := true
	// The order the graph file is written influences the arrangement
	// of nodes in the output image, so it makes sense to eliminate
	// randomness here. Unfortunately with graphviz it's fairly hard
	// to get a consistent ordering.
	for _, simNode := range network.Nodes {
		node := simNode.Gossip
		incoming := node.Incoming()
		for _, iNode := range incoming {
			e := edge{dest: node.GetNodeID()}
			key := fmt.Sprintf("%d:%d", iNode, node.GetNodeID())
			if _, ok := edgeSet[key]; !ok {
				e.added = true
				quiescent = false
			}
			delete(edgeSet, key)
			outgoingMap.addEdge(iNode, e)
		}
		if len(incoming) > maxIncoming {
			maxIncoming = len(incoming)
		}
	}

	// Find all edges which were deleted.
	for key, e := range edgeSet {
		e.added = false
		e.deleted = true
		quiescent = false
		nodeID, err := strconv.Atoi(strings.Split(key, ":")[0])
		if err != nil {
			log.Fatal(err)
		}
		outgoingMap.addEdge(roachpb.NodeID(nodeID), e)
		delete(edgeSet, key)
	}

	fmt.Fprintln(f, "digraph G {")
	fmt.Fprintln(f, "node [shape=record];")
	for _, simNode := range network.Nodes {
		node := simNode.Gossip
		var missing []roachpb.NodeID
		var totalAge int64
		for _, otherNode := range network.Nodes {
			if otherNode == simNode {
				continue // skip the node's own info
			}
			infoKey := otherNode.Addr.String()
			// GetInfo returns an error if the info is missing.
			if info, err := node.GetInfo(infoKey); err != nil {
				missing = append(missing, otherNode.Gossip.GetNodeID())
				quiescent = false
			} else {
				_, val, err := encoding.DecodeUint64Ascending(info)
				if err != nil {
					log.Fatalf("bad decode of node info cycle: %s", err)
//.........这里部分代码省略.........

func runDebugCheckStoreCmd(cmd *cobra.Command, args []string) error {
	stopper := stop.NewStopper()
	defer stopper.Stop()

	if len(args) != 1 {
		return errors.New("required arguments: dir")
	}

	db, err := openStore(cmd, args[0], stopper)
	if err != nil {
		return err
	}

	// Iterate over the entire range-id-local space.
	start := roachpb.Key(keys.LocalRangeIDPrefix)
	end := start.PrefixEnd()

	replicaInfo := map[roachpb.RangeID]*replicaCheckInfo{}
	getReplicaInfo := func(rangeID roachpb.RangeID) *replicaCheckInfo {
		if info, ok := replicaInfo[rangeID]; ok {
			return info
		}
		replicaInfo[rangeID] = &replicaCheckInfo{}
		return replicaInfo[rangeID]
	}

	if _, err := engine.MVCCIterate(context.Background(), db, start, end, hlc.MaxTimestamp,
		false /* !consistent */, nil, /* txn */
		false /* !reverse */, func(kv roachpb.KeyValue) (bool, error) {
			rangeID, _, suffix, detail, err := keys.DecodeRangeIDKey(kv.Key)
			if err != nil {
				return false, err
			}

			switch {
			case bytes.Equal(suffix, keys.LocalRaftTruncatedStateSuffix):
				var trunc roachpb.RaftTruncatedState
				if err := kv.Value.GetProto(&trunc); err != nil {
					return false, err
				}
				getReplicaInfo(rangeID).truncatedIndex = trunc.Index
			case bytes.Equal(suffix, keys.LocalRaftAppliedIndexSuffix):
				idx, err := kv.Value.GetInt()
				if err != nil {
					return false, err
				}
				getReplicaInfo(rangeID).appliedIndex = uint64(idx)
			case bytes.Equal(suffix, keys.LocalRaftLogSuffix):
				_, index, err := encoding.DecodeUint64Ascending(detail)
				if err != nil {
					return false, err
				}
				ri := getReplicaInfo(rangeID)
				if ri.firstIndex == 0 {
					ri.firstIndex = index
					ri.lastIndex = index
				} else {
					if index != ri.lastIndex+1 {
						fmt.Printf("range %s: log index anomaly: %v followed by %v\n",
							rangeID, ri.lastIndex, index)
					}
					ri.lastIndex = index
				}
			}

			return false, nil
		}); err != nil {
		return err
	}

	for rangeID, info := range replicaInfo {
		if info.truncatedIndex != info.firstIndex-1 {
			fmt.Printf("range %s: truncated index %v should equal first index %v - 1\n",
				rangeID, info.truncatedIndex, info.firstIndex)
		}
		if info.appliedIndex < info.firstIndex || info.appliedIndex > info.lastIndex {
			fmt.Printf("range %s: applied index %v should be between first index %v and last index %v\n",
				rangeID, info.appliedIndex, info.firstIndex, info.lastIndex)
		}
	}

	return nil
}