metrics: update some metrics buckets info

Author: zimulala

metrics/metrics.go

@@ -172,7 +172,7 @@ func initMetrics(namespace, subsystem string, constLabels prometheus.Labels) {
 			Subsystem:   subsystem,
 			Name:        "request_seconds",
 			Help:        "Bucketed histogram of sending request duration.",
-			Buckets:     prometheus.ExponentialBuckets(0.0005, 2, 29), // 0.5ms ~ 1.5days
+			Buckets:     prometheus.ExponentialBuckets(0.0005, 2, 24), // 0.5ms ~ 1.2h
 			ConstLabels: constLabels,
 		}, []string{LblType, LblStore, LblStaleRead, LblScope})
 
@@ -191,7 +191,7 @@ func initMetrics(namespace, subsystem string, constLabels prometheus.Labels) {
 			Subsystem:   subsystem,
 			Name:        "rpc_net_latency_seconds",
 			Help:        "Bucketed histogram of time difference between TiDB and TiKV.",
-			Buckets:     prometheus.ExponentialBuckets(5e-5, 2, 22), // 50us ~ 105s
+			Buckets:     prometheus.ExponentialBuckets(0.0001, 2, 20), // 0.1ms ~ 52s
 			ConstLabels: constLabels,
 		}, []string{LblStore, LblScope})
 
@@ -201,7 +201,7 @@ func initMetrics(namespace, subsystem string, constLabels prometheus.Labels) {
 			Subsystem:   subsystem,
 			Name:        "cop_duration_seconds",
 			Help:        "Run duration of a single coprocessor task, includes backoff time.",
-			Buckets:     prometheus.ExponentialBuckets(0.0005, 2, 29), // 0.5ms ~ 1.5days
+			Buckets:     prometheus.ExponentialBuckets(0.0005, 2, 24), // 0.5ms ~ 1.2h
 			ConstLabels: constLabels,
 		}, []string{LblStore, LblStaleRead, LblScope})