server: Add uptime status var and statistics

domain/infosync/info.go

@@ -856,7 +856,7 @@ func getServerInfo(id string, serverIDGetter func() uint64) *ServerInfo {
 
 	failpoint.Inject("mockServerInfo", func(val failpoint.Value) {
 		if val.(bool) {
-			info.StartTimestamp = 1282967700000
+			info.StartTimestamp = 1282967700
 			info.Labels = map[string]string{
 				"foo": "bar",
 			}

domain/infosync/info_test.go

@@ -72,7 +72,7 @@ func TestTopology(t *testing.T) {
 
 	topology, err := info.getTopologyFromEtcd(ctx)
 	require.NoError(t, err)
-	require.Equal(t, int64(1282967700000), topology.StartTimestamp)
+	require.Equal(t, int64(1282967700), topology.StartTimestamp)
 
 	v, ok := topology.Labels["foo"]
 	require.True(t, ok)
@@ -97,7 +97,7 @@ func TestTopology(t *testing.T) {
 
 	dir := path.Dir(s)
 	require.Equal(t, dir, topology.DeployPath)
-	require.Equal(t, int64(1282967700000), topology.StartTimestamp)
+	require.Equal(t, int64(1282967700), topology.StartTimestamp)
 	require.Equal(t, info.getTopologyInfo(), *topology)
 
 	// check ttl key

server/conn.go

@@ -59,6 +59,7 @@ import (
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/tidb/config"
+	"github.com/pingcap/tidb/domain/infosync"
 	"github.com/pingcap/tidb/errno"
 	"github.com/pingcap/tidb/executor"
 	"github.com/pingcap/tidb/infoschema"
@@ -1374,11 +1375,21 @@ func (cc *clientConn) dispatch(ctx context.Context, data []byte) error {
 }
 
 func (cc *clientConn) writeStats(ctx context.Context) error {
-	msg := []byte("Uptime: 0  Threads: 0  Questions: 0  Slow queries: 0  Opens: 0  Flush tables: 0  Open tables: 0  Queries per second avg: 0.000")
+	var err error
+	var uptime int64 = 0
+	info := serverInfo{}
+	info.ServerInfo, err = infosync.GetServerInfo()
+	if err != nil {
+		logutil.BgLogger().Error("Failed to get ServerInfo for uptime status", zap.Error(err))
+	} else {
+		uptime = int64(time.Since(time.Unix(info.ServerInfo.StartTimestamp, 0)).Seconds())
+	}
+	msg := []byte(fmt.Sprintf("Uptime: %d  Threads: 0  Questions: 0  Slow queries: 0  Opens: 0  Flush tables: 0  Open tables: 0  Queries per second avg: 0.000",
+		uptime))
 	data := cc.alloc.AllocWithLen(4, len(msg))
 	data = append(data, msg...)
 
-	err := cc.writePacket(data)
+	err = cc.writePacket(data)
 	if err != nil {
 		return err
 	}

server/stat.go

@@ -16,7 +16,9 @@ package server
 
 import (
 	"crypto/x509"
+	"time"
 
+	"github.com/pingcap/tidb/domain/infosync"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/util/logutil"
 	"go.uber.org/zap"
@@ -25,11 +27,13 @@ import (
 var (
 	serverNotAfter  = "Ssl_server_not_after"
 	serverNotBefore = "Ssl_server_not_before"
+	upTime          = "Uptime"
 )
 
 var defaultStatus = map[string]*variable.StatusVal{
 	serverNotAfter:  {Scope: variable.ScopeGlobal | variable.ScopeSession, Value: ""},
 	serverNotBefore: {Scope: variable.ScopeGlobal | variable.ScopeSession, Value: ""},
+	upTime:          {Scope: variable.ScopeGlobal, Value: 0},
 }
 
 // GetScope gets the status variables scope.
@@ -57,5 +61,15 @@ func (s *Server) Stats(vars *variable.SessionVars) (map[string]interface{}, erro
 			}
 		}
 	}
+
+	var err error
+	info := serverInfo{}
+	info.ServerInfo, err = infosync.GetServerInfo()
+	if err != nil {
+		logutil.BgLogger().Error("Failed to get ServerInfo for uptime status", zap.Error(err))
+	} else {
+		m[upTime] = int64(time.Since(time.Unix(info.ServerInfo.StartTimestamp, 0)).Seconds())
+	}
+
 	return m, nil
 }

server/stat_test.go

@@ -0,0 +1,61 @@
+// Copyright 2021 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package server
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/pingcap/failpoint"
+	"github.com/pingcap/tidb/domain/infosync"
+	"github.com/pingcap/tidb/session"
+	"github.com/pingcap/tidb/store/mockstore"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUptime(t *testing.T) {
+	var err error
+
+	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/domain/infosync/mockServerInfo", "return(true)"))
+	defer func() {
+		err := failpoint.Disable("github.com/pingcap/tidb/domain/infosync/mockServerInfo")
+		require.NoError(t, err)
+	}()
+
+	store, err := mockstore.NewMockStore()
+	require.NoError(t, err)
+
+	dom, err := session.BootstrapSession(store)
+	defer func() {
+		dom.Close()
+		err := store.Close()
+		require.NoError(t, err)
+	}()
+	require.NoError(t, err)
+
+	_, err = infosync.GlobalInfoSyncerInit(context.Background(), dom.DDL().GetID(), dom.ServerID, dom.GetEtcdClient(), true)
+	require.NoError(t, err)
+
+	tidbdrv := NewTiDBDriver(store)
+	cfg := newTestConfig()
+	cfg.Socket = ""
+	server, err := NewServer(cfg, tidbdrv)
+	require.NoError(t, err)
+
+	stats, err := server.Stats(nil)
+	require.NoError(t, err)
+	require.GreaterOrEqual(t, stats[upTime].(int64), int64(time.Since(time.Unix(1282967700, 0)).Seconds()))
+}