adding top queries execution collector

Author: Adrien ZAGABE

collector/pg_top_queries_execution.go

@@ -0,0 +1,165 @@
+package collector
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const statTopQueriesExecutionTime = "stat_top_queries"
+
+func init() {
+	registerCollector(statTopQueriesExecutionTime, true, NewPGStatTopQueriesExecutionTime)
+}
+
+type PGStatTopQueriesExecutionTime struct {
+	log log.Logger
+}
+
+func NewPGStatTopQueriesExecutionTime(config collectorConfig) (Collector, error) {
+	return &PGStatTopQueriesExecutionTime{log: config.logger}, nil
+}
+
+var (
+	statTotalExecutionTime = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statTopQueriesExecutionTime, "total_seconds"),
+		"Total time spent in the statement, in milliseconds",
+		[]string{"queryid", "datname", "user"},
+		prometheus.Labels{},
+	)
+	statMinimumExecutionTime = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statTopQueriesExecutionTime, "min_time_seconds"),
+		"Minimum time spent in the statement, in milliseconds",
+		[]string{"queryid", "datname", "user"},
+		prometheus.Labels{},
+	)
+
+	statMaximumExecutionTime = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statTopQueriesExecutionTime, "max_time_seconds"),
+		"Maximum time spent in the statement, in milliseconds",
+		[]string{"queryid", "datname", "user"},
+		prometheus.Labels{},
+	)
+
+	statMeanExecutionTime = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statTopQueriesExecutionTime, "mean_time"),
+		"Mean time spent in the statement, in milliseconds",
+		[]string{"queryid", "datname", "user"},
+		prometheus.Labels{},
+	)
+
+	statTopQueryExecutionQuery = `SELECT
+		pg_get_userbyid(userid) as user,
+		pg_database.datname,
+		pg_stat_statements.queryid,
+		pg_stat_statements.mean_time / 1000.0 as mean_time,
+		pg_stat_statements.total_time / 1000.0 as total_seconds,
+		pg_stat_statements.min_time / 1000.0 as min_time_seconds,
+		pg_stat_statements.max_time / 1000.0 as max_time_seconds,
+		pg_stat_statements.calls
+		FROM pg_stat_statements
+		JOIN pg_database
+			ON pg_database.id = pg_stat_statements.dbid
+		WHERE
+		total_time > (
+			SELECT percentile_cont(0.1)
+				WITHIN GROUP (ORDER BY total_time)
+				FROM pg_stat_statements
+			)
+		ORDER BY total_seconds DESC
+		LIMIT 100;`
+)
+
+func (PGStatTopQueriesExecutionTime) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	db := instance.getDB()
+	rows, err := db.QueryContext(ctx, statTopQueryExecutionQuery)
+
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var user, datName, queryid sql.NullString
+		var meanTime, totalSeconds, minTimeSeconds, maxTimeSeconds sql.NullFloat64
+		var calls sql.NullInt64
+
+		if err := rows.Scan(&user, &datName, &meanTime, &totalSeconds, &minTimeSeconds, &maxTimeSeconds, &calls); err != nil {
+			return err
+		}
+
+		userLabel := "unknown"
+		if user.Valid {
+			userLabel = user.String
+		}
+
+		datnameLabel := "unknown"
+		if datName.Valid {
+			datnameLabel = datName.String
+		}
+
+		queryIdLabel := "unknown"
+		if queryid.Valid {
+			queryIdLabel = queryid.String
+		}
+
+		totalSecondsMetric := 0.0
+		if totalSeconds.Valid {
+			totalSecondsMetric = totalSeconds.Float64
+		}
+		ch <- prometheus.MustNewConstMetric(
+			statTotalExecutionTime,
+			prometheus.CounterValue,
+			totalSecondsMetric,
+			userLabel, datnameLabel, queryIdLabel,
+		)
+
+		meanTimeSecondsMetric := 0.0
+		if meanTime.Valid {
+			meanTimeSecondsMetric = meanTime.Float64
+		}
+		ch <- prometheus.MustNewConstMetric(
+			statMeanExecutionTime,
+			prometheus.CounterValue,
+			meanTimeSecondsMetric,
+			userLabel, datnameLabel, queryIdLabel,
+		)
+
+		minTimeSecondsMetric := 0.0
+		if minTimeSeconds.Valid {
+			minTimeSecondsMetric = minTimeSeconds.Float64
+		}
+		ch <- prometheus.MustNewConstMetric(
+			statMinimumExecutionTime,
+			prometheus.CounterValue,
+			minTimeSecondsMetric,
+			userLabel, datnameLabel, queryIdLabel,
+		)
+
+		maxTimeSecondsMetric := 0.0
+		if maxTimeSeconds.Valid {
+			maxTimeSecondsMetric = maxTimeSeconds.Float64
+		}
+		ch <- prometheus.MustNewConstMetric(
+			statMaximumExecutionTime,
+			prometheus.CounterValue,
+			maxTimeSecondsMetric,
+			userLabel, datnameLabel, queryIdLabel,
+		)
+
+		callsMetric := 0.0
+		if calls.Valid {
+			callsMetric = float64(calls.Int64)
+		}
+
+		ch <- prometheus.MustNewConstMetric(
+			statTotalExecutionTime,
+			prometheus.CounterValue,
+			callsMetric,
+			userLabel, datnameLabel, queryIdLabel,
+		)
+	}
+	return nil
+}