sqlstats

A Go library for collecting sql.DBStats and exporting them in Prometheus format.

A sql.DB object represents a pool of zero or more underlying connections that get created and freed automatically. Connections in the pool may also be idle. There are a few settings (SetMaxOpenConns(), SetMaxIdleConns() and SetConnMaxLifetime()) that can be used to control the pool of connections. This library exposes stats about this pool in Prometheus format, to aid with understanding of the pool.

Installation

go get github.com/dlmiddlecote/sqlstats

Example

package main

import (
	"database/sql"
	"net/http"

	_ "github.com/lib/pq"
	"github.com/dlmiddlecote/sqlstats"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
	if err := run(); err != nil {
		panic(err)
	}
}

func run() error {
	// Open connection to a DB (could also use the https://github.com/jmoiron/sqlx library)
	db, err := sql.Open("postgres", "postgres://postgres:postgres@localhost:5432/postgres")
	if err != nil {
		return err
	}

	// Create a new collector, the name will be used as a label on the metrics
	collector := sqlstats.NewStatsCollector("db_name", db)

	// Register it with Prometheus
	prometheus.MustRegister(collector)

	// Register the metrics handler
	http.Handle("/metrics", promhttp.Handler())

	// Run the web server
	return http.ListenAndServe(":8080", nil)
}

Exposed Metrics

Name	Description	Labels	Go Version
go_sql_stats_connections_max_open	Maximum number of open connections to the database.	db_name	1.11+
go_sql_stats_connections_open	The number of established connections both in use and idle.	db_name	1.11+
go_sql_stats_connections_in_use	The number of connections currently in use.	db_name	1.11+
go_sql_stats_connections_idle	The number of idle connections.	db_name	1.11+
go_sql_stats_connections_waited_for	The total number of connections waited for.	db_name	1.11+
go_sql_stats_connections_blocked_seconds	The total time blocked waiting for a new connection.	db_name	1.11+
go_sql_stats_connections_closed_max_idle	The total number of connections closed due to SetMaxIdleConns.	db_name	1.11+
go_sql_stats_connections_closed_max_lifetime	The total number of connections closed due to SetConnMaxLifetime.	db_name	1.11+
go_sql_stats_connections_closed_max_idle_time	The total number of connections closed due to SetConnMaxIdleTime.	db_name	1.15+