Merge bd5a2866a4 into 2ce65c324c

collector/pg_long_running_transactions_summary.go

@@ -0,0 +1,109 @@
+// Copyright 2023 The Prometheus Authors
+// 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package collector
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const longRunningTransactionsSummarySubsystem = "long_running_transactions_summary"
+
+func init() {
+	registerCollector(longRunningTransactionsSummarySubsystem, defaultDisabled, NewPGLongRunningTransactionsSummaryCollector)
+}
+
+type PGLongRunningTransactionsSummaryCollector struct {
+	log log.Logger
+}
+
+func NewPGLongRunningTransactionsSummaryCollector(config collectorConfig) (Collector, error) {
+	return &PGLongRunningTransactionsSummaryCollector{log: config.logger}, nil
+}
+
+var (
+	longRunningTransactionsSummaryMaxAgeInSeconds = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, longRunningTransactionsSummarySubsystem, "max_age_in_seconds"),
+		"The current maximum transaction age in seconds",
+		[]string{"application", "endpoint"},
+		prometheus.Labels{},
+	)
+
+	longRunningTransactionsSummaryQuery = `
+	SELECT
+		activity.matches[1] AS application,
+		activity.matches[2] AS endpoint,
+		MAX(age_in_seconds) AS max_age_in_seconds
+	FROM (
+		SELECT
+		regexp_matches(query, '^\s*(?:\/\*(?:application:(\w+),?)?(?:correlation_id:\w+,?)?(?:jid:\w+,?)?(?:endpoint_id:([\w/\-\.:\#\s]+),?)?.*?\*\/)?\s*(\w+)') AS matches,
+		EXTRACT(EPOCH FROM (clock_timestamp() - xact_start)) AS age_in_seconds
+		FROM
+		pg_catalog.pg_stat_activity
+		WHERE state <> 'idle'
+		AND (clock_timestamp() - xact_start) > '30 seconds'::interval
+		AND query NOT LIKE 'autovacuum:%'
+		) activity
+	GROUP BY application, endpoint
+	ORDER BY max_age_in_seconds DESC
+	`
+)
+
+func (PGLongRunningTransactionsSummaryCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	db := instance.getDB()
+	rows, err := db.QueryContext(ctx,
+		longRunningTransactionsSummaryQuery)
+
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var application, endpoint sql.NullString
+		var maxAgeInSeconds sql.NullFloat64
+
+		if err := rows.Scan(&application, &endpoint, &maxAgeInSeconds); err != nil {
+			return err
+		}
+
+		applicationLabel := "unknown"
+		if application.Valid {
+			applicationLabel = application.String
+		}
+		endpointLabel := "unknown"
+		if endpoint.Valid {
+			endpointLabel = endpoint.String
+		}
+		labels := []string{applicationLabel, endpointLabel}
+
+		maxAgeInSecondsMetric := 0.0
+		if maxAgeInSeconds.Valid {
+			maxAgeInSecondsMetric = maxAgeInSeconds.Float64
+		}
+		ch <- prometheus.MustNewConstMetric(
+			longRunningTransactionsSummaryMaxAgeInSeconds,
+			prometheus.GaugeValue,
+			maxAgeInSecondsMetric,
+			labels...,
+		)
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	return nil
+}