fix: Only query active_time on pg>=14 (#1045)

Signed-off-by: MarcWort <113890636+MarcWort@users.noreply.github.com>

collector/pg_stat_database.go

@@ -16,7 +16,10 @@ package collector
 import (
 	"context"
 	"database/sql"
+	"fmt"
+	"strings"
 
+	"github.com/blang/semver/v4"
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
@@ -215,37 +218,44 @@ var (
 		[]string{"datid", "datname"},
 		prometheus.Labels{},
 	)
-
-	statDatabaseQuery = `
-		SELECT
-			datid
-			,datname
-			,numbackends
-			,xact_commit
-			,xact_rollback
-			,blks_read
-			,blks_hit
-			,tup_returned
-			,tup_fetched
-			,tup_inserted
-			,tup_updated
-			,tup_deleted
-			,conflicts
-			,temp_files
-			,temp_bytes
-			,deadlocks
-			,blk_read_time
-			,blk_write_time
-		    ,active_time
-			,stats_reset
-		FROM pg_stat_database;
-	`
 )
 
+func statDatabaseQuery(columns []string) string {
+	return fmt.Sprintf("SELECT %s FROM pg_stat_database;", strings.Join(columns, ","))
+}
+
 func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
 	db := instance.getDB()
+
+	columns := []string{
+		"datid",
+		"datname",
+		"numbackends",
+		"xact_commit",
+		"xact_rollback",
+		"blks_read",
+		"blks_hit",
+		"tup_returned",
+		"tup_fetched",
+		"tup_inserted",
+		"tup_updated",
+		"tup_deleted",
+		"conflicts",
+		"temp_files",
+		"temp_bytes",
+		"deadlocks",
+		"blk_read_time",
+		"blk_write_time",
+		"stats_reset",
+	}
+
+	activeTimeAvail := instance.version.GTE(semver.MustParse("14.0.0"))
+	if activeTimeAvail {
+		columns = append(columns, "active_time")
+	}
+
 	rows, err := db.QueryContext(ctx,
-		statDatabaseQuery,
+		statDatabaseQuery(columns),
 	)
 	if err != nil {
 		return err
@@ -257,7 +267,7 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 		var numBackends, xactCommit, xactRollback, blksRead, blksHit, tupReturned, tupFetched, tupInserted, tupUpdated, tupDeleted, conflicts, tempFiles, tempBytes, deadlocks, blkReadTime, blkWriteTime, activeTime sql.NullFloat64
 		var statsReset sql.NullTime
 
-		err := rows.Scan(
+		r := []any{
 			&datid,
 			&datname,
 			&numBackends,
@@ -276,9 +286,14 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 			&deadlocks,
 			&blkReadTime,
 			&blkWriteTime,
-			&activeTime,
 			&statsReset,
-		)
+		}
+
+		if activeTimeAvail {
+			r = append(r, &activeTime)
+		}
+
+		err := rows.Scan(r...)
 		if err != nil {
 			return err
 		}
@@ -355,7 +370,7 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 			level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no blk_write_time")
 			continue
 		}
-		if !activeTime.Valid {
+		if activeTimeAvail && !activeTime.Valid {
 			level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no active_time")
 			continue
 		}
@@ -482,19 +497,21 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 			labels...,
 		)
 
-		ch <- prometheus.MustNewConstMetric(
-			statDatabaseActiveTime,
-			prometheus.CounterValue,
-			activeTime.Float64/1000.0,
-			labels...,
-		)
-
 		ch <- prometheus.MustNewConstMetric(
 			statDatabaseStatsReset,
 			prometheus.CounterValue,
 			statsResetMetric,
 			labels...,
 		)
+
+		if activeTimeAvail {
+			ch <- prometheus.MustNewConstMetric(
+				statDatabaseActiveTime,
+				prometheus.CounterValue,
+				activeTime.Float64/1000.0,
+				labels...,
+			)
+		}
 	}
 	return nil
 }

collector/pg_stat_database_test.go

@@ -18,6 +18,7 @@ import (
 	"time"
 
 	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/blang/semver/v4"
 	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
@@ -31,7 +32,7 @@ func TestPGStatDatabaseCollector(t *testing.T) {
 	}
 	defer db.Close()
 
-	inst := &instance{db: db}
+	inst := &instance{db: db, version: semver.MustParse("14.0.0")}
 
 	columns := []string{
 		"datid",
@@ -52,8 +53,8 @@ func TestPGStatDatabaseCollector(t *testing.T) {
 		"deadlocks",
 		"blk_read_time",
 		"blk_write_time",
-		"active_time",
 		"stats_reset",
+		"active_time",
 	}
 
 	srT, err := time.Parse("2006-01-02 15:04:05.00000-07", "2023-05-25 17:10:42.81132-07")
@@ -81,10 +82,11 @@ func TestPGStatDatabaseCollector(t *testing.T) {
 			925,
 			16,
 			823,
+			srT,
 			33,
-			srT)
+		)
 
-	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery)).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery(columns))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
@@ -115,8 +117,8 @@ func TestPGStatDatabaseCollector(t *testing.T) {
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 925},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 16},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 823},
-		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.033},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 1685059842},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.033},
 	}
 
 	convey.Convey("Metrics comparison", t, func() {
@@ -141,7 +143,7 @@ func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Error parsing time: %s", err)
 	}
-	inst := &instance{db: db}
+	inst := &instance{db: db, version: semver.MustParse("14.0.0")}
 
 	columns := []string{
 		"datid",
@@ -162,8 +164,8 @@ func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 		"deadlocks",
 		"blk_read_time",
 		"blk_write_time",
-		"active_time",
 		"stats_reset",
+		"active_time",
 	}
 
 	rows := sqlmock.NewRows(columns).
@@ -186,8 +188,9 @@ func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 			925,
 			16,
 			823,
+			srT,
 			32,
-			srT).
+		).
 		AddRow(
 			"pid",
 			"postgres",
@@ -207,9 +210,10 @@ func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 			925,
 			16,
 			823,
+			srT,
 			32,
-			srT)
+		)
-	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery)).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery(columns))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
@@ -240,8 +244,8 @@ func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 925},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 16},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 823},
-		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.032},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 1685059842},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.032},
 	}
 
 	convey.Convey("Metrics comparison", t, func() {
@@ -261,7 +265,7 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 	}
 	defer db.Close()
 
-	inst := &instance{db: db}
+	inst := &instance{db: db, version: semver.MustParse("14.0.0")}
 
 	columns := []string{
 		"datid",
@@ -282,8 +286,8 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 		"deadlocks",
 		"blk_read_time",
 		"blk_write_time",
-		"active_time",
 		"stats_reset",
+		"active_time",
 	}
 
 	srT, err := time.Parse("2006-01-02 15:04:05.00000-07", "2023-05-25 17:10:42.81132-07")
@@ -311,8 +315,9 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 			925,
 			16,
 			823,
+			srT,
 			14,
-			srT).
+		).
 		AddRow(
 			nil,
 			nil,
@@ -354,9 +359,10 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 			926,
 			17,
 			824,
+			srT,
 			15,
-			srT)
+		)
-	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery)).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery(columns))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
@@ -387,8 +393,8 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 925},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 16},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 823},
-		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.014},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 1685059842},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.014},
 
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_GAUGE, value: 355},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 4946},
@@ -406,8 +412,8 @@ func TestPGStatDatabaseCollectorRowLeakTest(t *testing.T) {
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 926},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 17},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 824},
-		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.015},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 1685059842},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.015},
 	}
 
 	convey.Convey("Metrics comparison", t, func() {
@@ -428,7 +434,7 @@ func TestPGStatDatabaseCollectorTestNilStatReset(t *testing.T) {
 	}
 	defer db.Close()
 
-	inst := &instance{db: db}
+	inst := &instance{db: db, version: semver.MustParse("14.0.0")}
 
 	columns := []string{
 		"datid",
@@ -449,8 +455,8 @@ func TestPGStatDatabaseCollectorTestNilStatReset(t *testing.T) {
 		"deadlocks",
 		"blk_read_time",
 		"blk_write_time",
-		"active_time",
 		"stats_reset",
+		"active_time",
 	}
 
 	rows := sqlmock.NewRows(columns).
@@ -473,10 +479,11 @@ func TestPGStatDatabaseCollectorTestNilStatReset(t *testing.T) {
 			925,
 			16,
 			823,
+			nil,
 			7,
-			nil)
+		)
 
-	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery)).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery(columns))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
@@ -507,8 +514,8 @@ func TestPGStatDatabaseCollectorTestNilStatReset(t *testing.T) {
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 925},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 16},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 823},
-		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.007},
 		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.007},
 	}
 
 	convey.Convey("Metrics comparison", t, func() {