tidb, domain: schema lease metrics (pingcap#2417)

domain/domain.go

@@ -254,9 +254,12 @@ func (do *Domain) Reload() error {
 	}
 
 	latestSchemaVersion, err = do.loadInfoSchema(do.infoHandle, schemaVersion, ver.Ver)
+	loadSchemaDuration.Observe(time.Since(startTime).Seconds())
 	if err != nil {
+		loadSchemaCounter.WithLabelValues("failed").Inc()
 		return errors.Trace(err)
 	}
+	loadSchemaCounter.WithLabelValues("succ").Inc()
 
 	do.SchemaValidator.Update(ver.Ver, latestSchemaVersion)
 

domain/metrics.go

@@ -0,0 +1,42 @@
+// Copyright 2017 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 domain
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	loadSchemaCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "tidb",
+			Subsystem: "domain",
+			Name:      "load_schema_total",
+			Help:      "Counter of load schema",
+		}, []string{"type"})
+
+	loadSchemaDuration = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "tidb",
+			Subsystem: "domain",
+			Name:      "load_schema_duration",
+			Help:      "Bucketed histogram of processing time (s) in load schema.",
+			Buckets:   prometheus.ExponentialBuckets(0.001, 2, 15),
+		})
+)
+
+func init() {
+	prometheus.MustRegister(loadSchemaDuration)
+	prometheus.MustRegister(loadSchemaCounter)
+}

metrics.go

@@ -42,10 +42,18 @@ var (
 			Help:      "Bucketed histogram of processing time (s) in running executor.",
 			Buckets:   prometheus.ExponentialBuckets(0.0001, 2, 13),
 		})
+	schemaLeaseErrorCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "tidb",
+			Subsystem: "server",
+			Name:      "schema_lease_error_counter",
+			Help:      "Counter of schema lease error",
+		}, []string{"type"})
 )
 
 func init() {
 	prometheus.MustRegister(sessionExecuteParseDuration)
 	prometheus.MustRegister(sessionExecuteCompileDuration)
 	prometheus.MustRegister(sessionExecuteRunDuration)
+	prometheus.MustRegister(schemaLeaseErrorCounter)
 }

session.go

@@ -167,8 +167,10 @@ func (s *schemaLeaseChecker) Check(txnTS uint64) error {
 		case nil:
 			return nil
 		case domain.ErrInfoSchemaChanged:
+			schemaLeaseErrorCounter.WithLabelValues("changed").Inc()
 			return errors.Trace(err)
 		default:
+			schemaLeaseErrorCounter.WithLabelValues("outdated").Inc()
 			time.Sleep(schemaOutOfDateRetryInterval)
 		}
 	}