Add more metrics for *sql.DB (#3230)

Closes #2909.
FerretDB · Aug 23, 2023 · a78b98a · a78b98a
1 parent 7049116
commit a78b98a
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Showing 2 changed files with 60 additions and 3 deletions.
diff --git a/internal/backends/sqlite/metadata/registry.go b/internal/backends/sqlite/metadata/registry.go
@@ -362,7 +362,7 @@ func (r *Registry) Collect(ch chan<- prometheus.Metric) {
 	r.p.Collect(ch)
 
 	r.rw.RLock()
-	defer r.rw.RLock()
+	defer r.rw.RUnlock()
 
 	ch <- prometheus.MustNewConstMetric(
 		prometheus.NewDesc(

diff --git a/internal/util/fsql/metrics.go b/internal/util/fsql/metrics.go
@@ -71,8 +71,65 @@ func (c *metricsCollector) Collect(ch chan<- prometheus.Metric) {
 		float64(stats.OpenConnections),
 	)
 
-	// Add other metrics from stats here.
-	// TODO https://github.com/FerretDB/FerretDB/issues/2909
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "in_use"),
+			"The number of connections currently in use.",
+			nil, c.labels,
+		),
+		prometheus.GaugeValue,
+		float64(stats.InUse),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "idle"),
+			"The number of idle connections.",
+			nil, c.labels,
+		),
+		prometheus.GaugeValue,
+		float64(stats.Idle),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "wait_count_total"),
+			"The total number of connections waited for.",
+			nil, c.labels,
+		),
+		prometheus.CounterValue,
+		float64(stats.WaitCount),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "wait_duration_seconds_total"),
+			"The total time blocked waiting for a new connection.",
+			nil, c.labels,
+		),
+		prometheus.CounterValue,
+		float64(stats.WaitDuration.Seconds()),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "max_idle_closed_total"),
+			"The total number of connections closed due to SetMaxIdleConns.",
+			nil, c.labels,
+		),
+		prometheus.CounterValue,
+		float64(stats.MaxIdleClosed),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, "max_idle_time_closed_total"),
+			"The total number of connections closed due to SetConnMaxIdleTime.",
+			nil, c.labels,
+		),
+		prometheus.CounterValue,
+		float64(stats.MaxIdleTimeClosed),
+	)
 
 	ch <- prometheus.MustNewConstMetric(
 		prometheus.NewDesc(