Add metrics from pg_stat_user_indexes

README.md

@@ -9,7 +9,10 @@ Prometheus exporter for PostgreSQL server metrics.
 - stat_archiver
 - stat_bgwriter
 - stat_database
+- stat_progress_vacuum
 - stat_replication
+- stat_user_indexes
+- stat_user_tables
 - info
 - locks
 
@@ -69,6 +72,9 @@ Prometheus exporter for PostgreSQL server metrics.
 | postgres_stat_vacuum_progress_phase_vacuuming_heap | VACUUM is currently vacuuming the heap | pid, query_start, schemaname, datname, relname |
 | postgres_stat_vacuum_progress_phase_vacuuming_indexes | VACUUM is currently vacuuming the indexes | pid, query_start, schemaname, datname, relname |
 | postgres_stat_vacuum_progress_running | VACUUM is running | pid, query_start, schemaname, datname, relname |
+| postgres_stat_user_indexes_scan_total | Number of times this index has been scanned | datname, schemaname, tablename, indexname |
+| postgres_stat_user_indexes_tuple_read_total | Number of times tuples have been returned from scanning this index | datname, schemaname, tablename, indexname |
+| postgres_stat_user_indexes_tuple_fetch_total | Number of live tuples fetched by scans on this index | datname, schemaname, tablename, indexname |
 | postgres_up | Whether the Postgres server is up | |
 
 ### Run

collector/exporter.go

@@ -103,6 +103,7 @@ func NewExporter(ctx context.Context, logger kitlog.Logger, connConfig *pgx.Conn
 		datnameScrapers: []Scraper{
 			NewStatVacuumProgressScraper(),
 			NewStatUserTablesScraper(),
+			NewStatUserIndexesScraper(),
 			NewDiskUsageScraper(),
 		},
 	}

collector/stat_user_indexes.go

@@ -0,0 +1,103 @@
+package collector
+
+import (
+	"context"
+
+	pgx "github.com/jackc/pgx/v4"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// The Statistics Scraper
+// PostgreSQL's statistics collector is a subsystem that supports collection and reporting of information about
+// server activity. Presently, the collector can count accesses to tables and indexes in both disk-block and
+// individual-row terms. It also tracks the total number of rows in each table, and information about vacuum
+// and analyze actions for each table. It can also count calls to user-defined functions and the total time
+// spent in each one.
+//https://www.postgresql.org/docs/9.4/static/monitoring-stats.html#PG-STAT-ALL-INDEXES-VIEW
+const (
+	// Scrape query
+	statUserIndexesQuery = `
+SELECT schemaname
+     , relname
+     , indexrelname
+     , idx_scan::float
+     , idx_tup_read::float
+     , idx_tup_fetch::float
+  FROM pg_stat_user_indexes
+ WHERE schemaname != 'information_schema'
+  AND idx_tup_fetch IS NOT NULL /*postgres_exporter*/`
+)
+
+type statUserIndexesScraper struct {
+	idxScan     *prometheus.Desc
+	idxTupRead  *prometheus.Desc
+	idxTupFetch *prometheus.Desc
+}
+
+// NewStatUserIndexesScraper returns a new Scraper exposing postgres pg_stat_user_indexes view
+func NewStatUserIndexesScraper() Scraper {
+	return &statUserIndexesScraper{
+		idxScan: prometheus.NewDesc(
+			"postgres_stat_user_indexes_scan_total",
+			"Number of times this index has been scanned",
+			[]string{"datname", "schemaname", "relname", "indexname"},
+			nil,
+		),
+		idxTupRead: prometheus.NewDesc(
+			"postgres_stat_user_indexes_tuple_read_total",
+			"Number of times tuples have been returned from scanning this index",
+			[]string{"datname", "schemaname", "relname", "indexname"},
+			nil,
+		),
+		idxTupFetch: prometheus.NewDesc(
+			"postgres_stat_user_indexes_tuple_fetch_total",
+			"Number of live tuples fetched by scans on this index",
+			[]string{"datname", "schemaname", "relname", "indexname"},
+			nil,
+		),
+	}
+}
+
+func (c *statUserIndexesScraper) Name() string {
+	return "StatUserIndexesScraper"
+}
+
+func (c *statUserIndexesScraper) Scrape(ctx context.Context, conn *pgx.Conn, version Version, ch chan<- prometheus.Metric) error {
+	var datname string
+	if err := conn.QueryRow(ctx, "SELECT current_database() /*postgres_exporter*/").Scan(&datname); err != nil {
+		return err
+	}
+
+	rows, err := conn.Query(ctx, statUserIndexesQuery)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	var schemaname, relname, indexname string
+	var idxScan, idxTupRead, idxTupFetch float64
+	for rows.Next() {
+		if err := rows.Scan(&schemaname,
+			&relname,
+			&indexname,
+			&idxScan,
+			&idxTupRead,
+			&idxTupFetch); err != nil {
+			return err
+		}
+
+		// postgres_stat_user_indexes_idx_scan_total
+		ch <- prometheus.MustNewConstMetric(c.idxScan, prometheus.CounterValue, idxScan, datname, schemaname, relname, indexname)
+		// postgres_stat_user_indexes_idx_tup_read_total
+		ch <- prometheus.MustNewConstMetric(c.idxTupRead, prometheus.CounterValue, idxTupRead, datname, schemaname, relname, indexname)
+		// postgres_stat_user_indexes_idx_tup_fetch_total
+		ch <- prometheus.MustNewConstMetric(c.idxTupFetch, prometheus.CounterValue, idxTupFetch, datname, schemaname, relname, indexname)
+	}
+
+	err = rows.Err()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}