metrics: remove Keep Alive OPM metric

metrics/metrics.go

@@ -124,7 +124,6 @@ func RegisterMetrics() {
 	prometheus.MustRegister(SyncLoadHistogram)
 	prometheus.MustRegister(ReadStatsHistogram)
 	prometheus.MustRegister(JobsGauge)
-	prometheus.MustRegister(KeepAliveCounter)
 	prometheus.MustRegister(LoadPrivilegeCounter)
 	prometheus.MustRegister(InfoCacheCounters)
 	prometheus.MustRegister(LoadSchemaCounter)

metrics/server.go

@@ -120,14 +120,6 @@ var (
 			Help:      "Counter of system time jumps backward.",
 		})
 
-	KeepAliveCounter = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: "tidb",
-			Subsystem: "monitor",
-			Name:      "keep_alive_total",
-			Help:      "Counter of TiDB keep alive.",
-		})
-
 	PlanCacheCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: "tidb",

tidb-server/main.go

@@ -788,16 +788,7 @@ func setupMetrics() {
 	systimeErrHandler := func() {
 		metrics.TimeJumpBackCounter.Inc()
 	}
-	callBackCount := 0
-	successCallBack := func() {
-		callBackCount++
-		// It is callback by monitor per second, we increase metrics.KeepAliveCounter per 5s.
-		if callBackCount >= 5 {
-			callBackCount = 0
-			metrics.KeepAliveCounter.Inc()
-		}
-	}
-	go systimemon.StartMonitor(time.Now, systimeErrHandler, successCallBack)
+	go systimemon.StartMonitor(time.Now, systimeErrHandler)
 
 	pushMetric(cfg.Status.MetricsAddr, time.Duration(cfg.Status.MetricsInterval)*time.Second)
 }

util/systimemon/systime_mon.go

@@ -22,23 +22,16 @@ import (
 )
 
 // StartMonitor calls systimeErrHandler if system time jump backward.
-func StartMonitor(now func() time.Time, systimeErrHandler func(), successCallback func()) {
+func StartMonitor(now func() time.Time, systimeErrHandler func()) {
 	logutil.BgLogger().Info("start system time monitor")
 	tick := time.NewTicker(100 * time.Millisecond)
 	defer tick.Stop()
-	tickCount := 0
 	for {
 		last := now().UnixNano()
 		<-tick.C
 		if now().UnixNano() < last {
 			logutil.BgLogger().Error("system time jump backward", zap.Int64("last", last))
 			systimeErrHandler()
 		}
-		// call successCallback per second.
-		tickCount++
-		if tickCount >= 10 {
-			tickCount = 0
-			successCallback()
-		}
 	}
 }

util/systimemon/systime_mon_test.go

@@ -35,7 +35,7 @@ func TestSystimeMonitor(t *testing.T) {
 			return time.Now().Add(-2 * time.Second)
 		}, func() {
 			errTriggered.Store(true)
-		}, func() {})
+		})
 
 	require.Eventually(t, errTriggered.Load, time.Second, 10*time.Millisecond)
 }