gc(ticdc): add min service gc safe point metrics (#10553)

ref #10463

cdc/server/metrics.go

@@ -28,6 +28,7 @@ import (
 	"github.com/pingcap/tiflow/pkg/orchestrator"
 	"github.com/pingcap/tiflow/pkg/p2p"
 	"github.com/pingcap/tiflow/pkg/sink/observer"
+	"github.com/pingcap/tiflow/pkg/txnutil/gc"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
 	tikvmetrics "github.com/tikv/client-go/v2/metrics"
@@ -55,6 +56,7 @@ func init() {
 	redo.InitMetrics(registry)
 	scheduler.InitMetrics(registry)
 	observer.InitMetrics(registry)
+	gc.InitMetrics(registry)
 	// TiKV client metrics, including metrics about resolved and region cache.
 	originalRegistry := prometheus.DefaultRegisterer
 	prometheus.DefaultRegisterer = registry

metrics/grafana/ticdc.json

@@ -3202,7 +3202,7 @@
           },
           "gridPos": {
             "h": 7,
-            "w": 12,
+            "w": 6,
             "x": 0,
             "y": 3
           },
@@ -3260,8 +3260,8 @@
           "grid": {},
           "gridPos": {
             "h": 7,
-            "w": 12,
-            "x": 12,
+            "w": 6,
+            "x": 6,
             "y": 3
           },
           "hiddenSeries": false,
@@ -3353,6 +3353,111 @@
             "alignLevel": null
           }
         },
+        {
+          "aliasColors": {},
+          "bars": false,
+          "dashLength": 10,
+          "dashes": false,
+          "datasource": "${DS_TEST-CLUSTER}",
+          "fieldConfig": {
+            "defaults": {
+              "unit": "dateTimeAsIso"
+            },
+            "overrides": []
+          },
+          "fill": 1,
+          "fillGradient": 0,
+          "gridPos": {
+            "h": 7,
+            "w": 12,
+            "x": 12,
+            "y": 3
+          },
+          "hiddenSeries": false,
+          "id": 10037,
+          "legend": {
+            "avg": false,
+            "current": true,
+            "max": false,
+            "min": false,
+            "show": true,
+            "total": false,
+            "values": true
+          },
+          "lines": true,
+          "linewidth": 1,
+          "nullPointMode": "null",
+          "options": {
+            "alertThreshold": true
+          },
+          "percentage": false,
+          "pluginVersion": "7.5.10",
+          "pointradius": 2,
+          "points": false,
+          "renderer": "flot",
+          "seriesOverrides": [],
+          "spaceLength": 10,
+          "stack": false,
+          "steppedLine": false,
+          "targets": [
+            {
+              "exemplar": true,
+              "expr": "max(ticdc_gc_min_service_gc_safepoint{})",
+              "interval": "",
+              "legendFormat": "gc time",
+              "queryType": "randomWalk",
+              "refId": "A"
+            },
+            {
+              "exemplar": true,
+              "expr": "max(ticdc_gc_cdc_gc_safepoint{})",
+              "hide": false,
+              "interval": "",
+              "legendFormat": "cdc service safepoint",
+              "refId": "B"
+            }
+          ],
+          "thresholds": [],
+          "timeFrom": null,
+          "timeRegions": [],
+          "timeShift": null,
+          "title": "GC Time",
+          "tooltip": {
+            "shared": true,
+            "sort": 0,
+            "value_type": "individual"
+          },
+          "type": "graph",
+          "xaxis": {
+            "buckets": null,
+            "mode": "time",
+            "name": null,
+            "show": true,
+            "values": []
+          },
+          "yaxes": [
+            {
+              "format": "dateTimeAsIso",
+              "label": null,
+              "logBase": 1,
+              "max": null,
+              "min": null,
+              "show": true
+            },
+            {
+              "format": "short",
+              "label": null,
+              "logBase": 1,
+              "max": null,
+              "min": null,
+              "show": true
+            }
+          ],
+          "yaxis": {
+            "align": false,
+            "alignLevel": null
+          }
+        },
         {
           "aliasColors": {},
           "bars": true,
@@ -21777,4 +21882,4 @@
   "title": "${DS_TEST-CLUSTER}-TiCDC",
   "uid": "YiGL8hBZ1",
   "version": 57
-}
+}

pkg/txnutil/gc/gc_manager.go

@@ -103,6 +103,8 @@ func (m *gcManager) TryUpdateGCSafePoint(
 	m.isTiCDCBlockGC.Store(actual == checkpointTs)
 	m.lastSafePointTs = actual
 	m.lastSucceededTime = time.Now()
+	minServiceGCSafePointGauge.Set(float64(oracle.ExtractPhysical(actual)))
+	cdcGCSafePointGauge.Set(float64(oracle.ExtractPhysical(checkpointTs)))
 	return nil
 }
 

pkg/txnutil/gc/metrics.go

@@ -0,0 +1,42 @@
+// Copyright 2020 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,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gc
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	minServiceGCSafePointGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "ticdc",
+			Subsystem: "gc",
+			Name:      "min_service_gc_safepoint",
+			Help:      "The min value all of service GC safepoint",
+		})
+
+	cdcGCSafePointGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "ticdc",
+			Subsystem: "gc",
+			Name:      "cdc_gc_safepoint",
+			Help:      "the value of CDC GC safepoint",
+		})
+)
+
+// InitMetrics registers all metrics used gc manager
+func InitMetrics(registry *prometheus.Registry) {
+	registry.MustRegister(minServiceGCSafePointGauge)
+	registry.MustRegister(cdcGCSafePointGauge)
+}