Collect idle_in_transaction_time from PG >= 15

idle_in_transaction_time was added to pg_stat_database in pg 15

Signed-off-by: Alexander J. Maidak <amaidak@equinix.com>

collector/pg_stat_database.go

@@ -218,6 +218,15 @@ var (
 		[]string{"datid", "datname"},
 		prometheus.Labels{},
 	)
+	statDatabaseIdleInTransaction = prometheus.NewDesc(prometheus.BuildFQName(
+		namespace,
+		statDatabaseSubsystem,
+		"idle_in_transaction_time_seconds_total",
+	),
+		"Time spent idling while in a transaction in this database, in seconds",
+		[]string{"datid", "datname"},
+		prometheus.Labels{},
+	)
 )
 
 func statDatabaseQuery(columns []string) string {
@@ -254,6 +263,11 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 		columns = append(columns, "active_time")
 	}
 
+	idleInTransactionTimeAvail := instance.version.GTE(semver.MustParse("15.0.0"))
+	if idleInTransactionTimeAvail {
+		columns = append(columns, "idle_in_transaction_time")
+	}
+
 	rows, err := db.QueryContext(ctx,
 		statDatabaseQuery(columns),
 	)
@@ -264,7 +278,7 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 
 	for rows.Next() {
 		var datid, datname sql.NullString
-		var numBackends, xactCommit, xactRollback, blksRead, blksHit, tupReturned, tupFetched, tupInserted, tupUpdated, tupDeleted, conflicts, tempFiles, tempBytes, deadlocks, blkReadTime, blkWriteTime, activeTime sql.NullFloat64
+		var numBackends, xactCommit, xactRollback, blksRead, blksHit, tupReturned, tupFetched, tupInserted, tupUpdated, tupDeleted, conflicts, tempFiles, tempBytes, deadlocks, blkReadTime, blkWriteTime, activeTime, idleInTransactionTime sql.NullFloat64
 		var statsReset sql.NullTime
 
 		r := []any{
@@ -293,6 +307,10 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 			r = append(r, &activeTime)
 		}
 
+		if idleInTransactionTimeAvail {
+			r = append(r, &idleInTransactionTime)
+		}
+
 		err := rows.Scan(r...)
 		if err != nil {
 			return err
@@ -375,6 +393,11 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 			continue
 		}
 
+		if idleInTransactionTimeAvail && !idleInTransactionTime.Valid {
+			level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no idle_in_transaction_time")
+			continue
+		}
+
 		statsResetMetric := 0.0
 		if !statsReset.Valid {
 			level.Debug(c.log).Log("msg", "No metric for stats_reset, will collect 0 instead")
@@ -512,6 +535,15 @@ func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance
 				labels...,
 			)
 		}
+
+		if idleInTransactionTimeAvail {
+			ch <- prometheus.MustNewConstMetric(
+				statDatabaseIdleInTransaction,
+				prometheus.CounterValue,
+				idleInTransactionTime.Float64/1000.0,
+				labels...,
+			)
+		}
 	}
 	return nil
 }

collector/pg_stat_database_test.go

@@ -132,6 +132,116 @@ func TestPGStatDatabaseCollector(t *testing.T) {
 	}
 }
 
+func TestPGStatDatabaseCollectorCollectsIdleTime(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("Error opening a stub db connection: %s", err)
+	}
+	defer db.Close()
+
+	inst := &instance{db: db, version: semver.MustParse("15.0.0")}
+
+	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",
+		"active_time",
+		"idle_in_transaction_time",
+	}
+
+	srT, err := time.Parse("2006-01-02 15:04:05.00000-07", "2023-05-25 17:10:42.81132-07")
+	if err != nil {
+		t.Fatalf("Error parsing time: %s", err)
+	}
+
+	rows := sqlmock.NewRows(columns).
+		AddRow(
+			"pid",
+			"postgres",
+			354,
+			4945,
+			289097744,
+			1242257,
+			int64(3275602074),
+			89320867,
+			450139,
+			2034563757,
+			0,
+			int64(2725688749),
+			23,
+			52,
+			74,
+			925,
+			16,
+			823,
+			srT,
+			33,
+			123,
+		)
+
+	mock.ExpectQuery(sanitizeQuery(statDatabaseQuery(columns))).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := PGStatDatabaseCollector{
+			log: log.With(log.NewNopLogger(), "collector", "pg_stat_database"),
+		}
+
+		if err := c.Update(context.Background(), inst, ch); err != nil {
+			t.Errorf("Error calling PGStatDatabaseCollector.Update: %s", err)
+		}
+	}()
+
+	expected := []MetricResult{
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_GAUGE, value: 354},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 4945},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 289097744},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 1242257},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 3275602074},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 89320867},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 450139},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 2034563757},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 2725688749},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 23},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 52},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 74},
+		{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: 1685059842},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.033},
+		{labels: labelMap{"datid": "pid", "datname": "postgres"}, metricType: dto.MetricType_COUNTER, value: 0.123},
+	}
+
+	convey.Convey("Metrics comparison", t, func() {
+		for _, expect := range expected {
+			m := readMetric(<-ch)
+			convey.So(expect, convey.ShouldResemble, m)
+		}
+	})
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled exceptions: %s", err)
+	}
+}
+
 func TestPGStatDatabaseCollectorNullValues(t *testing.T) {
 	db, mock, err := sqlmock.New()
 	if err != nil {