Deprecated WithMinimumReadDBStatsInterval option

This option is not necessary since database/sql.DB.Stats calls are
cheap. Note that go.opentelemetry.io/contrib/instrumentation/runtime
instrumentation has a similar option WithMinimumReadMemStatsInterval,
but for runtime.ReadMemStats that actually has a noticable performance
impact (it does stopTheWorld to read stats).

database/sql.DB.Stats, on the other hand, simply acquires a mutex for a
short duration to return a consistent snapshot of database statistics.

Author: tie

options.go

@@ -227,20 +227,18 @@ func TraceLastInsertID() DriverOption {
 	})
 }
 
-// WithMinimumReadDBStatsInterval sets the minimum interval between calls to db.Stats(). Negative values are ignored.
-func WithMinimumReadDBStatsInterval(interval time.Duration) StatsOption {
-	return statsOptionFunc(func(o *statsOptions) {
-		o.minimumReadDBStatsInterval = interval
-	})
+// WithMinimumReadDBStatsInterval does nothing.
+//
+// Deprecated: does not have any effect since [database/sql.DB.Stats] calls are
+// cheap.
+func WithMinimumReadDBStatsInterval(_ time.Duration) StatsOption {
+	return statsOptionFunc(func(_ *statsOptions) {})
 }
 
 type statsOptions struct {
 	// meterProvider sets the metric.MeterProvider. If nil, the global Provider will be used.
 	meterProvider metric.MeterProvider
 
-	// minimumReadDBStatsInterval sets the minimum interval between calls to db.Stats(). Negative values are ignored.
-	minimumReadDBStatsInterval time.Duration
-
 	// defaultAttributes will be set to each metrics as default.
 	defaultAttributes []attribute.KeyValue
 }

stats.go

@@ -4,16 +4,12 @@ import (
 	"context"
 	"database/sql"
 	"sync"
-	"time"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 )
 
-// defaultMinimumReadDBStatsInterval is the default minimum interval between calls to db.Stats().
-const defaultMinimumReadDBStatsInterval = time.Second
-
 const (
 	dbSQLConnectionsOpen           = "db.sql.connections.open"
 	dbSQLConnectionsIdle           = "db.sql.connections.idle"
@@ -28,8 +24,7 @@ const (
 // RecordStats records database statistics for provided sql.DB at the provided interval.
 func RecordStats(db *sql.DB, opts ...StatsOption) error {
 	o := statsOptions{
-		meterProvider:              otel.GetMeterProvider(),
-		minimumReadDBStatsInterval: defaultMinimumReadDBStatsInterval,
+		meterProvider: otel.GetMeterProvider(),
 	}
 
 	for _, opt := range opts {
@@ -38,14 +33,13 @@ func RecordStats(db *sql.DB, opts ...StatsOption) error {
 
 	meter := o.meterProvider.Meter(instrumentationName)
 
-	return recordStats(meter, db, o.minimumReadDBStatsInterval, o.defaultAttributes...)
+	return recordStats(meter, db, o.defaultAttributes...)
 }
 
 // nolint: funlen
 func recordStats(
 	meter metric.Meter,
 	db *sql.DB,
-	minimumReadDBStatsInterval time.Duration,
 	attrs ...attribute.KeyValue,
 ) error {
 	var (
@@ -60,9 +54,6 @@ func recordStats(
 		idleTimeClosed    metric.Int64ObservableCounter
 		lifetimeClosed    metric.Int64ObservableCounter
 
-		dbStats     sql.DBStats
-		lastDBStats time.Time
-
 		// lock prevents a race between batch observer and instrument registration.
 		lock sync.Mutex
 	)
@@ -130,11 +121,7 @@ func recordStats(
 		lock.Lock()
 		defer lock.Unlock()
 
-		now := time.Now()
-		if now.Sub(lastDBStats) >= minimumReadDBStatsInterval {
-			dbStats = db.Stats()
-			lastDBStats = now
-		}
+		dbStats := db.Stats()
 
 		obs.ObserveInt64(openConnections, int64(dbStats.OpenConnections), metric.WithAttributes(attrs...))
 		obs.ObserveInt64(idleConnections, int64(dbStats.Idle), metric.WithAttributes(attrs...))