func TestCheckVersion(t *testing.T) {
	defer leaktest.AfterTest(t)()

	updateChecks := int32(0)
	uuid := ""
	version := ""

	recorder := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer r.Body.Close()
		atomic.AddInt32(&updateChecks, 1)
		uuid = r.URL.Query().Get("uuid")
		version = r.URL.Query().Get("version")
	}))

	s := StartTestServer(t)
	s.parsedUpdatesURL, _ = url.Parse(recorder.URL)
	s.checkForUpdates()
	recorder.Close()
	s.Stop()

	if expected, actual := int32(1), atomic.LoadInt32(&updateChecks); actual != expected {
		t.Fatalf("expected %v update checks, got %v", expected, actual)
	}

	if expected, actual := s.node.ClusterID.String(), uuid; expected != actual {
		t.Errorf("expected uuid %v, got %v", expected, actual)
	}

	if expected, actual := build.GetInfo().Tag, version; expected != actual {
		t.Errorf("expected version tag %v, got %v", expected, actual)
	}
}

func runGenManCmd(cmd *cobra.Command, args []string) error {
	info := build.GetInfo()
	header := &doc.GenManHeader{
		Section: "1",
		Manual:  "CockroachDB Manual",
		Source:  fmt.Sprintf("CockroachDB %s", info.Tag),
	}

	if !strings.HasSuffix(manPath, string(os.PathSeparator)) {
		manPath += string(os.PathSeparator)
	}

	if _, err := os.Stat(manPath); err != nil {
		if os.IsNotExist(err) {
			if err := os.MkdirAll(manPath, 0755); err != nil {
				return err
			}
		} else {
			return err
		}
	}

	if err := doc.GenManTree(cmd.Root(), header, manPath); err != nil {
		return err
	}

	// TODO(cdo): The man page generated by the cobra package doesn't include a list of commands, so
	// one has to notice the "See Also" section at the bottom of the page to know which commands
	// are supported. I'd like to make this better somehow.

	fmt.Println("Generated CockroachDB man pages in", manPath)
	return nil
}

func (s *Server) reportUsage() {
	b := new(bytes.Buffer)
	if err := json.NewEncoder(b).Encode(s.getReportingInfo()); err != nil {
		log.Warning(context.TODO(), err)
		return
	}

	q := reportingURL.Query()
	q.Set("version", build.GetInfo().Tag)
	q.Set("uuid", s.node.ClusterID.String())
	reportingURL.RawQuery = q.Encode()

	res, err := http.Post(reportingURL.String(), "application/json", b)
	if err != nil && log.V(2) {
		// This is probably going to be relatively common in production
		// environments where network access is usually curtailed.
		log.Warning(context.TODO(), "Failed to report node usage metrics: ", err)
		return
	}

	if res.StatusCode != http.StatusOK {
		b, err := ioutil.ReadAll(res.Body)
		log.Warningf(context.TODO(), "Failed to report node usage metrics: status: %s, body: %s, "+
			"error: %v", res.Status, b, err)
	}
}

func (s *adminServer) ClusterFreeze(
	ctx context.Context, req *ClusterFreezeRequest,
) (*ClusterFreezeResponse, error) {
	var resp ClusterFreezeResponse
	stores := make(map[roachpb.StoreID]roachpb.NodeID)
	process := func(from, to roachpb.Key) (roachpb.Key, error) {
		b := &client.Batch{}
		fa := roachpb.NewChangeFrozen(from, to, req.Freeze, build.GetInfo().Tag)
		b.AddRawRequest(fa)
		if err := s.server.db.Run(b); err != nil {
			return nil, err
		}
		fr := b.RawResponse().Responses[0].GetInner().(*roachpb.ChangeFrozenResponse)
		resp.RangesAffected += fr.RangesAffected
		for storeID, nodeID := range fr.Stores {
			stores[storeID] = nodeID
		}
		return fr.MinStartKey.AsRawKey(), nil
	}

	if req.Freeze {
		// When freezing, we save the meta2 and meta1 range for last to avoid
		// interfering with command routing.
		// Note that we freeze only Ranges whose StartKey is included. In
		// particular, a Range which contains some meta keys will not be frozen
		// by the request that begins at Meta2KeyMax. ChangeFreeze gives us the
		// leftmost covered Range back, which we use for the next request to
		// avoid split-related races.
		freezeTo := roachpb.KeyMax // updated as we go along
		freezeFroms := []roachpb.Key{
			keys.Meta2KeyMax, // freeze userspace
			keys.Meta1KeyMax, // freeze all meta2 ranges
			keys.LocalMax,    // freeze first range (meta1)
		}

		for _, freezeFrom := range freezeFroms {
			var err error
			if freezeTo, err = process(freezeFrom, freezeTo); err != nil {
				return nil, err
			}
		}
	} else {
		// When unfreezing, we walk in opposite order and try the first range
		// first. We should be able to get there if the first range manages to
		// gossip. From that, we can talk to the second level replicas, and
		// then to everyone else. Because ChangeFrozen works in forward order,
		// we can simply hit the whole keyspace at once.
		// TODO(tschottdorf): make the first range replicas gossip their
		// descriptor unconditionally or we won't always be able to unfreeze
		// (except by restarting a node which holds the first range).
		if _, err := process(keys.LocalMax, roachpb.KeyMax); err != nil {
			return nil, err
		}
	}
	return &resp, s.waitForStoreFrozen(stores, req.Freeze)
}

// GetStatusSummary returns a status summary messages for the node. The summary
// includes the recent values of metrics for both the node and all of its
// component stores.
func (mr *MetricsRecorder) GetStatusSummary() *NodeStatus {
	mr.mu.Lock()
	defer mr.mu.Unlock()

	if mr.mu.nodeRegistry == nil {
		// We haven't yet processed initialization information; do nothing.
		if log.V(1) {
			log.Warning(context.TODO(), "MetricsRecorder.GetStatusSummary called before NodeID allocation.")
		}
		return nil
	}

	now := mr.mu.clock.PhysicalNow()

	// Generate an node status with no store data.
	nodeStat := &NodeStatus{
		Desc:          mr.mu.desc,
		BuildInfo:     build.GetInfo(),
		UpdatedAt:     now,
		StartedAt:     mr.mu.startedAt,
		StoreStatuses: make([]StoreStatus, 0, mr.mu.lastSummaryCount),
		Metrics:       make(map[string]float64, mr.mu.lastNodeMetricCount),
	}

	eachRecordableValue(mr.mu.nodeRegistry, func(name string, val float64) {
		nodeStat.Metrics[name] = val
	})

	// Generate status summaries for stores.
	for storeID, r := range mr.mu.storeRegistries {
		storeMetrics := make(map[string]float64, mr.mu.lastStoreMetricCount)
		eachRecordableValue(r, func(name string, val float64) {
			storeMetrics[name] = val
		})

		// Gather descriptor from store.
		descriptor, err := mr.mu.stores[storeID].Descriptor()
		if err != nil {
			log.Errorf(context.TODO(), "Could not record status summaries: Store %d could not return descriptor, error: %s", storeID, err)
			continue
		}

		nodeStat.StoreStatuses = append(nodeStat.StoreStatuses, StoreStatus{
			Desc:    *descriptor,
			Metrics: storeMetrics,
		})
	}
	mr.mu.lastSummaryCount = len(nodeStat.StoreStatuses)
	mr.mu.lastNodeMetricCount = len(nodeStat.Metrics)
	if len(nodeStat.StoreStatuses) > 0 {
		mr.mu.lastStoreMetricCount = len(nodeStat.StoreStatuses[0].Metrics)
	}
	return nodeStat
}

// TestStatusJson verifies that status endpoints return expected Json results.
// The content type of the responses is always util.JSONContentType.
func TestStatusJson(t *testing.T) {
	defer leaktest.AfterTest(t)()
	s, _, _ := serverutils.StartServer(t, base.TestServerArgs{})
	defer s.Stopper().Stop()
	ts := s.(*TestServer)

	nodeID := ts.Gossip().GetNodeID()
	addr, err := ts.Gossip().GetNodeIDAddress(nodeID)
	if err != nil {
		t.Fatal(err)
	}

	var nodes serverpb.NodesResponse
	util.SucceedsSoon(t, func() error {
		if err := getRequestProto(t, s, statusNodesPrefix, &nodes); err != nil {
			t.Fatal(err)
		}

		if len(nodes.Nodes) == 0 {
			return errors.Errorf("expected non-empty node list, got: %v", nodes)
		}
		return nil
	})

	for _, path := range []string{
		"/health",
		"/_status/details/local",
		"/_status/details/" + strconv.FormatUint(uint64(nodeID), 10),
	} {
		var details serverpb.DetailsResponse
		if err := getRequestProto(t, s, path, &details); err != nil {
			t.Fatal(err)
		}
		if a, e := details.NodeID, nodeID; a != e {
			t.Errorf("expected: %d, got: %d", e, a)
		}
		if a, e := details.Address, *addr; a != e {
			t.Errorf("expected: %v, got: %v", e, a)
		}
		if a, e := details.BuildInfo, build.GetInfo(); a != e {
			t.Errorf("expected: %v, got: %v", e, a)
		}
	}
}

// rotateFile closes the syncBuffer's file and starts a new one.
func (sb *syncBuffer) rotateFile(now time.Time) error {
	if sb.file != nil {
		if err := sb.Flush(); err != nil {
			return err
		}
		if err := sb.file.Close(); err != nil {
			return err
		}
	}
	var err error
	sb.file, _, err = create(sb.sev, now)
	sb.nbytes = 0
	if err != nil {
		return err
	}

	sb.Writer = bufio.NewWriterSize(sb.file, bufferSize)

	f, l, _ := caller.Lookup(1)
	for _, msg := range []string{
		fmt.Sprintf("[config] file created at: %s\n", now.Format("2006/01/02 15:04:05")),
		fmt.Sprintf("[config] running on machine: %s\n", host),
		fmt.Sprintf("[config] binary: %s\n", build.GetInfo().Short()),
		fmt.Sprintf("[config] arguments: %s\n", os.Args),
		fmt.Sprintf("line format: [IWEF]yymmdd hh:mm:ss.uuuuuu goid file:line msg\n"),
	} {
		buf := formatLogEntry(Entry{
			Severity:  sb.sev,
			Time:      now.UnixNano(),
			Goroutine: goid.Get(),
			File:      f,
			Line:      int64(l),
			Message:   msg,
		}, nil, nil)
		var n int
		n, err = sb.file.Write(buf.Bytes())
		sb.nbytes += uint64(n)
		if err != nil {
			return err
		}
		logging.putBuffer(buf)
	}
	return nil
}

// Details returns node details.
func (s *statusServer) Details(ctx context.Context, req *serverpb.DetailsRequest) (*serverpb.DetailsResponse, error) {
	nodeID, local, err := s.parseNodeID(req.NodeId)
	if err != nil {
		return nil, grpc.Errorf(codes.InvalidArgument, err.Error())
	}
	if local {
		resp := &serverpb.DetailsResponse{
			NodeID:    s.gossip.GetNodeID(),
			BuildInfo: build.GetInfo(),
		}
		if addr, err := s.gossip.GetNodeIDAddress(s.gossip.GetNodeID()); err == nil {
			resp.Address = *addr
		}
		return resp, nil
	}
	status, err := s.dialNode(nodeID)
	if err != nil {
		return nil, err
	}
	return status.Details(ctx, req)
}

func (s *Server) checkForUpdates() {
	q := updatesURL.Query()
	q.Set("version", build.GetInfo().Tag)
	q.Set("uuid", s.node.ClusterID.String())
	updatesURL.RawQuery = q.Encode()

	res, err := http.Get(updatesURL.String())
	if err != nil {
		// This is probably going to be relatively common in production
		// environments where network access is usually curtailed.
		if log.V(2) {
			log.Warning(context.TODO(), "Failed to check for updates: ", err)
		}
		return
	}
	defer res.Body.Close()

	if res.StatusCode != http.StatusOK {
		b, err := ioutil.ReadAll(res.Body)
		log.Warningf(context.TODO(), "Failed to check for updates: status: %s, body: %s, error: %v",
			res.Status, b, err)
		return
	}

	decoder := json.NewDecoder(res.Body)
	r := struct {
		Details []versionInfo `json:"details"`
	}{}

	err = decoder.Decode(&r)
	if err != nil && err != io.EOF {
		log.Warning(context.TODO(), "Error decoding updates info: ", err)
		return
	}

	for _, v := range r.Details {
		log.Infof(context.TODO(), "A new version is available: %s, details: %s", v.Version, v.Details)
	}
}

func (s *Server) checkForUpdates() {
	// Don't phone home in tests (SetupReportingURLs is called in cli/start.go).
	if s.parsedUpdatesURL == nil {
		return
	}

	q := s.parsedUpdatesURL.Query()
	q.Set("version", build.GetInfo().Tag)
	q.Set("uuid", s.node.ClusterID.String())
	s.parsedUpdatesURL.RawQuery = q.Encode()

	res, err := http.Get(s.parsedUpdatesURL.String())
	if err != nil {
		// This is probably going to be relatively common in production
		// environments where network access is usually curtailed.
		if log.V(2) {
			log.Warning("Error checking for updates: ", err)
		}
		return
	}
	defer res.Body.Close()

	decoder := json.NewDecoder(res.Body)
	r := struct {
		Details []versionInfo `json:"details"`
	}{}

	err = decoder.Decode(&r)
	if err != nil && err != io.EOF {
		log.Warning("Error decoding updates info: ", err)
		return
	}

	for _, v := range r.Details {
		log.Infof("A new version is available: %s, details: %s", v.Version, v.Details)
	}
}

// MakeRuntimeStatSampler constructs a new RuntimeStatSampler object.
func MakeRuntimeStatSampler(clock *hlc.Clock) RuntimeStatSampler {
	// Construct the build info metric. It is constant.
	// We first build set the labels on the metadata.
	info := build.GetInfo()
	timestamp, err := info.Timestamp()
	if err != nil {
		// We can't panic here, tests don't have a build timestamp.
		log.Warningf(context.TODO(), "Could not parse build timestamp: %v", err)
	}

	metaBuildTimestamp.AddLabel("tag", info.Tag)
	metaBuildTimestamp.AddLabel("go_version", info.GoVersion)

	buildTimestamp := metric.NewGauge(metaBuildTimestamp)
	buildTimestamp.Update(timestamp)

	return RuntimeStatSampler{
		clock:          clock,
		startTimeNanos: clock.PhysicalNow(),
		CgoCalls:       metric.NewGauge(metaCgoCalls),
		Goroutines:     metric.NewGauge(metaGoroutines),
		GoAllocBytes:   metric.NewGauge(metaGoAllocBytes),
		GoTotalBytes:   metric.NewGauge(metaGoTotalBytes),
		CgoAllocBytes:  metric.NewGauge(metaCgoAllocBytes),
		CgoTotalBytes:  metric.NewGauge(metaCgoTotalBytes),
		GcCount:        metric.NewGauge(metaGCCount),
		GcPauseNS:      metric.NewGauge(metaGCPauseNS),
		GcPausePercent: metric.NewGaugeFloat64(metaGCPausePercent),
		CPUUserNS:      metric.NewGauge(metaCPUUserNS),
		CPUUserPercent: metric.NewGaugeFloat64(metaCPUUserPercent),
		CPUSysNS:       metric.NewGauge(metaCPUSysNS),
		CPUSysPercent:  metric.NewGaugeFloat64(metaCPUSysPercent),
		Rss:            metric.NewGauge(metaRSS),
		Uptime:         metric.NewGauge(metaUptime),
		BuildTimestamp: buildTimestamp,
	}
}

func (s *Server) reportUsage() {
	// Don't phone home in tests (SetupReportingURLs is called in cli/start.go).
	if s.parsedReportingURL == nil {
		return
	}

	b := new(bytes.Buffer)
	if err := json.NewEncoder(b).Encode(s.getReportingInfo()); err != nil {
		log.Warning(err)
		return
	}

	q := s.parsedReportingURL.Query()
	q.Set("version", build.GetInfo().Tag)
	q.Set("uuid", s.node.ClusterID.String())
	s.parsedReportingURL.RawQuery = q.Encode()

	_, err := http.Post(s.parsedReportingURL.String(), "application/json", b)
	if err != nil && log.V(2) {
		// This is probably going to be relatively common in production
		// environments where network access is usually curtailed.
		log.Warning("Error checking reporting node usage metrics: ", err)
	}
}

//.........这里部分代码省略.........
			// all stores in our tests have identical values; when comparing
			// status summaries, the same map is used as expected data for all
			// stores.
			expectedStoreSummaryMetrics[prefix+name] = float64(val)
		}
	}

	for _, reg := range regList {
		for _, data := range metricNames {
			switch data.typ {
			case "gauge":
				reg.reg.Gauge(data.name).Update(data.val)
				addExpected(reg.prefix, data.name, reg.source, 100, data.val, reg.isNode)
			case "floatgauge":
				reg.reg.GaugeFloat64(data.name).Update(float64(data.val))
				addExpected(reg.prefix, data.name, reg.source, 100, data.val, reg.isNode)
			case "counter":
				reg.reg.Counter(data.name).Inc(data.val)
				addExpected(reg.prefix, data.name, reg.source, 100, data.val, reg.isNode)
			case "rate":
				reg.reg.Rates(data.name).Add(data.val)
				addExpected(reg.prefix, data.name+"-count", reg.source, 100, data.val, reg.isNode)
				for _, scale := range metric.DefaultTimeScales {
					// Rate data is subject to timing errors in tests. Zero out
					// these values.
					addExpected(reg.prefix, data.name+sep+scale.Name(), reg.source, 100, 0, reg.isNode)
				}
			case "histogram":
				reg.reg.Histogram(data.name, time.Second, 1000, 2).RecordValue(data.val)
				for _, q := range recordHistogramQuantiles {
					addExpected(reg.prefix, data.name+q.suffix, reg.source, 100, data.val, reg.isNode)
				}
			case "latency":
				reg.reg.Latency(data.name).RecordValue(data.val)
				// Latency is simply three histograms (at different resolution
				// time scales).
				for _, scale := range metric.DefaultTimeScales {
					for _, q := range recordHistogramQuantiles {
						addExpected(reg.prefix, data.name+sep+scale.Name()+q.suffix, reg.source, 100, data.val, reg.isNode)
					}
				}
			}
		}
	}

	// ========================================
	// Verify time series data
	// ========================================
	actual := recorder.GetTimeSeriesData()

	// Zero-out timing-sensitive rate values from actual data.
	for _, act := range actual {
		match, err := regexp.MatchString(`testRate-\d+m`, act.Name)
		if err != nil {
			t.Fatal(err)
		}
		if match {
			act.Datapoints[0].Value = 0.0
		}
	}

	// Actual comparison is simple: sort the resulting arrays by time and name,
	// and use reflect.DeepEqual.
	sort.Sort(byTimeAndName(actual))
	sort.Sort(byTimeAndName(expected))
	if a, e := actual, expected; !reflect.DeepEqual(a, e) {
		t.Errorf("recorder did not yield expected time series collection; diff:\n %v", pretty.Diff(e, a))
	}

	// ========================================
	// Verify node summary generation
	// ========================================
	expectedNodeSummary := &NodeStatus{
		Desc:      nodeDesc,
		BuildInfo: build.GetInfo(),
		StartedAt: 50,
		UpdatedAt: 100,
		Metrics:   expectedNodeSummaryMetrics,
		StoreStatuses: []StoreStatus{
			{
				Desc:    storeDesc1,
				Metrics: expectedStoreSummaryMetrics,
			},
			{
				Desc:    storeDesc2,
				Metrics: expectedStoreSummaryMetrics,
			},
		},
	}

	nodeSummary := recorder.GetStatusSummary()
	if nodeSummary == nil {
		t.Fatalf("recorder did not return nodeSummary.")
	}

	sort.Sort(byStoreDescID(nodeSummary.StoreStatuses))
	if a, e := nodeSummary, expectedNodeSummary; !reflect.DeepEqual(a, e) {
		t.Errorf("recorder did not produce expected NodeSummary; diff:\n %v", pretty.Diff(e, a))
	}
}

	"github.com/spf13/cobra"
)

// Proxy to allow overrides in tests.
var osStderr = os.Stderr

var versionIncludesDeps bool

var versionCmd = &cobra.Command{
	Use:   "version",
	Short: "output version information",
	Long: `
Output build version information.
`,
	Run: func(cmd *cobra.Command, args []string) {
		info := build.GetInfo()
		tw := tabwriter.NewWriter(os.Stdout, 2, 1, 2, ' ', 0)
		fmt.Fprintf(tw, "Build Tag:   %s\n", info.Tag)
		fmt.Fprintf(tw, "Build Time:  %s\n", info.Time)
		fmt.Fprintf(tw, "Platform:    %s\n", info.Platform)
		fmt.Fprintf(tw, "Go Version:  %s\n", info.GoVersion)
		fmt.Fprintf(tw, "C Compiler:  %s\n", info.CgoCompiler)
		if versionIncludesDeps {
			fmt.Fprintf(tw, "Build Deps:\n\t%s\n",
				strings.Replace(strings.Replace(info.Dependencies, " ", "\n\t", -1), ":", "\t", -1))
		}
		_ = tw.Flush()
	},
}

var cockroachCmd = &cobra.Command{

func checkNodeStatus(t *testing.T, c cliTest, output string, start time.Time) {
	buf := bytes.NewBufferString(output)
	s := bufio.NewScanner(buf)

	// Skip command line.
	if !s.Scan() {
		t.Fatalf("Couldn't skip command line: %s", s.Err())
	}

	checkSeparatorLine(t, s)

	// check column names.
	if !s.Scan() {
		t.Fatalf("Error reading column names: %s", s.Err())
	}
	cols, err := extractFields(s.Text())
	if err != nil {
		t.Fatalf("%s", err)
	}
	if !reflect.DeepEqual(cols, nodesColumnHeaders) {
		t.Fatalf("columns (%s) don't match expected (%s)", cols, nodesColumnHeaders)
	}

	checkSeparatorLine(t, s)

	// Check node status.
	if !s.Scan() {
		t.Fatalf("error reading node status: %s", s.Err())
	}
	fields, err := extractFields(s.Text())
	if err != nil {
		t.Fatalf("%s", err)
	}

	nodeID := c.Gossip().GetNodeID()
	nodeIDStr := strconv.FormatInt(int64(nodeID), 10)
	if a, e := fields[0], nodeIDStr; a != e {
		t.Errorf("node id (%s) != expected (%s)", a, e)
	}

	nodeAddr, err := c.Gossip().GetNodeIDAddress(nodeID)
	if err != nil {
		t.Fatal(err)
	}
	if a, e := fields[1], nodeAddr.String(); a != e {
		t.Errorf("node address (%s) != expected (%s)", a, e)
	}

	// Verify Build Tag.
	if a, e := fields[2], build.GetInfo().Tag; a != e {
		t.Errorf("build tag (%s) != expected (%s)", a, e)
	}

	// Verify that updated_at and started_at are reasonably recent.
	// CircleCI can be very slow. This was flaky at 5s.
	checkTimeElapsed(t, fields[3], 15*time.Second, start)
	checkTimeElapsed(t, fields[4], 15*time.Second, start)

	// Verify all byte/range metrics.
	testcases := []struct {
		name   string
		idx    int
		maxval int64
	}{
		{"live_bytes", 5, 30000},
		{"key_bytes", 6, 30000},
		{"value_bytes", 7, 30000},
		{"intent_bytes", 8, 30000},
		{"system_bytes", 9, 30000},
		{"leader_ranges", 10, 3},
		{"repl_ranges", 11, 3},
		{"avail_ranges", 12, 3},
	}
	for _, tc := range testcases {
		val, err := strconv.ParseInt(fields[tc.idx], 10, 64)
		if err != nil {
			t.Errorf("couldn't parse %s '%s': %v", tc.name, fields[tc.idx], err)
			continue
		}
		if val < 0 {
			t.Errorf("value for %s (%d) cannot be less than 0", tc.name, val)
			continue
		}
		if val > tc.maxval {
			t.Errorf("value for %s (%d) greater than max (%d)", tc.name, val, tc.maxval)
		}
	}

	checkSeparatorLine(t, s)
}

	"trunc": {
		floatBuiltin1(func(x float64) (Datum, error) {
			return NewDFloat(DFloat(math.Trunc(x))), nil
		}),
		decimalBuiltin1(func(x *inf.Dec) (Datum, error) {
			dd := &DDecimal{}
			dd.Round(x, 0, inf.RoundDown)
			return dd, nil
		}),
	},
	"version": {
		Builtin{
			Types:      ArgTypes{},
			ReturnType: TypeString,
			fn: func(_ EvalContext, args DTuple) (Datum, error) {
				return NewDString(build.GetInfo().Short()), nil
			},
		},
	},
}

// The aggregate functions all just return their first argument. We don't
// perform any type checking here either. The bulk of the aggregate function
// implementation is performed at a higher level in sql.groupNode.
func aggregateImpls(types ...Datum) []Builtin {
	var r []Builtin
	for _, t := range types {
		r = append(r, Builtin{
			Types:      ArgTypes{t},
			ReturnType: t,
		})

func initBacktrace(logDir string) *stop.Stopper {
	const ptracePath = "/opt/backtrace/bin/ptrace"
	if _, err := os.Stat(ptracePath); err != nil {
		log.Infof(context.TODO(), "backtrace disabled: %s", err)
		return stop.NewStopper()
	}

	if err := bcd.EnableTracing(); err != nil {
		log.Infof(context.TODO(), "unable to enable backtrace: %s", err)
		return stop.NewStopper()
	}

	bcd.UpdateConfig(bcd.GlobalConfig{
		PanicOnKillFailure: true,
		ResendSignal:       true,
		RateLimit:          time.Second * 3,
		SynchronousPut:     true,
	})

	// Use the default tracer implementation.
	// false: Exclude system goroutines.
	tracer := bcd.New(bcd.NewOptions{
		IncludeSystemGs: false,
	})
	if err := tracer.SetOutputPath(logDir, 0755); err != nil {
		log.Infof(context.TODO(), "unable to set output path: %s", err)
		// Not a fatal error, continue.
	}

	// Enable WARNING log output from the tracer.
	tracer.AddOptions(nil, "-L", "WARNING")

	info := build.GetInfo()
	tracer.AddKV(nil, "cgo-compiler", info.CgoCompiler)
	tracer.AddKV(nil, "go-version", info.GoVersion)
	tracer.AddKV(nil, "platform", info.Platform)
	tracer.AddKV(nil, "tag", info.Tag)
	tracer.AddKV(nil, "time", info.Time)

	// Register for traces on signal reception.
	tracer.SetSigset(
		[]os.Signal{
			syscall.SIGABRT,
			syscall.SIGFPE,
			syscall.SIGSEGV,
			syscall.SIGILL,
			syscall.SIGBUS}...)
	bcd.Register(tracer)

	// Hook log.Fatal*.
	log.SetExitFunc(func(code int) {
		_ = bcd.Trace(tracer, fmt.Errorf("exit %d", code), nil)
		os.Exit(code)
	})

	stopper := stop.NewStopper(stop.OnPanic(func(val interface{}) {
		err, ok := val.(error)
		if !ok {
			err = fmt.Errorf("%v", val)
		}
		_ = bcd.Trace(tracer, err, nil)
		panic(val)
	}))

	// Internally, backtrace uses an external program (/opt/backtrace/bin/ptrace)
	// to generate traces. We direct the stdout for this program to a file for
	// debugging our usage of backtrace.
	if f, err := os.OpenFile(filepath.Join(logDir, "backtrace.out"),
		os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666); err != nil {
		log.Infof(context.TODO(), "unable to open: %s", err)
	} else {
		stopper.AddCloser(stop.CloserFn(func() {
			f.Close()
		}))
		tracer.SetPipes(nil, f)
	}

	tracer.SetLogLevel(bcd.LogMax)
	log.Infof(context.TODO(), "backtrace enabled")
	return stopper
}