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add frontend_used_ratio metric and username/database labels to frontend_used metric #9

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fe31db8
add pgpool2_frontend_used_ratio metric
n-oden Nov 10, 2021
84d2f67
add username/db labels for frontend_used counter
n-oden Nov 17, 2021
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1 change: 1 addition & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,7 @@ name | Pgpool-II Version | Description
:---|:---|:---
pgpool2_frontend_total | 3.6+ | Number of total child processes
pgpool2_frontend_used | 3.6+ | Number of used child processes
pgpool2_frontend_used_ratio | 3.6+ | Ratio of used child processes to total child processes (0.0 to 1.0)
pgpool2_pool_nodes_status | 3.6+ | Backend node Status (1 for up or waiting, 0 for down or unused)
pgpool2_pool_nodes_replication_delay | 3.6+ | Replication delay
pgpool2_pool_nodes_select_cnt | 3.6+ | SELECT query counts issued to each backend
Expand Down
161 changes: 93 additions & 68 deletions pgpool2_exporter.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,22 +23,21 @@ SOFTWARE.
package main

import (
"database/sql"
"errors"
"fmt"
"math"
"net/http"
"net/url"
"os"
"database/sql"
"errors"
"math"
"regexp"
"strconv"
"sync"
"time"


"github.com/blang/semver"
"github.com/go-kit/kit/log/level"
_ "github.com/lib/pq"
"github.com/blang/semver"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/prometheus/common/promlog"
Expand All @@ -48,14 +47,14 @@ import (
)

var (
listenAddress = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9719").String()
metricsPath = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
logger = promlog.New(&promlog.Config{})
listenAddress = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9719").String()
metricsPath = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
logger = promlog.New(&promlog.Config{})
)

const (
namespace = "pgpool2"
exporter = "exporter"
namespace = "pgpool2"
exporter = "exporter"
landingPage = `
<html>
<head>
Expand Down Expand Up @@ -153,69 +152,69 @@ type ColumnMapping struct {
// Exporter collects Pgpool-II stats from the given server and exports
// them using the prometheus metrics package.
type Exporter struct {
dsn string
namespace string
mutex sync.RWMutex
duration prometheus.Gauge
up prometheus.Gauge
error prometheus.Gauge
totalScrapes prometheus.Counter
metricMap map[string]MetricMapNamespace
db *sql.DB
dsn string
namespace string
mutex sync.RWMutex
duration prometheus.Gauge
up prometheus.Gauge
error prometheus.Gauge
totalScrapes prometheus.Counter
metricMap map[string]MetricMapNamespace
db *sql.DB
}

var (
metricMaps = map[string]map[string]ColumnMapping{
"pool_nodes": {
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"select_cnt": {GAUGE, "SELECT statement counts issued to each backend"},
"replication_delay": {GAUGE, "Replication delay"},
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"select_cnt": {GAUGE, "SELECT statement counts issued to each backend"},
"replication_delay": {GAUGE, "Replication delay"},
},
"pool_backend_stats": {
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"select_cnt": {GAUGE, "SELECT statement counts issued to each backend"},
"insert_cnt": {GAUGE, "INSERT statement counts issued to each backend"},
"update_cnt": {GAUGE, "UPDATE statement counts issued to each backend"},
"delete_cnt": {GAUGE, "DELETE statement counts issued to each backend"},
"ddl_cnt": {GAUGE, "DDL statement counts issued to each backend"},
"other_cnt": {GAUGE, "other statement counts issued to each backend"},
"panic_cnt": {GAUGE, "Panic message counts returned from backend"},
"fatal_cnt": {GAUGE, "Fatal message counts returned from backend)"},
"error_cnt": {GAUGE, "Error message counts returned from backend"},
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"select_cnt": {GAUGE, "SELECT statement counts issued to each backend"},
"insert_cnt": {GAUGE, "INSERT statement counts issued to each backend"},
"update_cnt": {GAUGE, "UPDATE statement counts issued to each backend"},
"delete_cnt": {GAUGE, "DELETE statement counts issued to each backend"},
"ddl_cnt": {GAUGE, "DDL statement counts issued to each backend"},
"other_cnt": {GAUGE, "other statement counts issued to each backend"},
"panic_cnt": {GAUGE, "Panic message counts returned from backend"},
"fatal_cnt": {GAUGE, "Fatal message counts returned from backend)"},
"error_cnt": {GAUGE, "Error message counts returned from backend"},
},
"pool_health_check_stats": {
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"total_count": {GAUGE, "Number of health check count in total"},
"success_count": {GAUGE, "Number of successful health check count in total"},
"fail_count": {GAUGE, "Number of failed health check count in total"},
"skip_count": {GAUGE, "Number of skipped health check count in total"},
"retry_count": {GAUGE, "Number of retried health check count in total"},
"average_retry_count": {GAUGE, "Number of average retried health check count in a health check session"},
"max_retry_count": {GAUGE, "Number of maximum retried health check count in a health check session"},
"max_duration": {GAUGE, "Maximum health check duration in Millie seconds"},
"min_duration": {GAUGE, "Minimum health check duration in Millie seconds"},
"average_duration": {GAUGE, "Average health check duration in Millie seconds"},
"hostname": {LABEL, "Backend hostname"},
"port": {LABEL, "Backend port"},
"role": {LABEL, "Role (primary or standby)"},
"status": {GAUGE, "Backend node Status (1 for up or waiting, 0 for down or unused)"},
"total_count": {GAUGE, "Number of health check count in total"},
"success_count": {GAUGE, "Number of successful health check count in total"},
"fail_count": {GAUGE, "Number of failed health check count in total"},
"skip_count": {GAUGE, "Number of skipped health check count in total"},
"retry_count": {GAUGE, "Number of retried health check count in total"},
"average_retry_count": {GAUGE, "Number of average retried health check count in a health check session"},
"max_retry_count": {GAUGE, "Number of maximum retried health check count in a health check session"},
"max_duration": {GAUGE, "Maximum health check duration in Millie seconds"},
"min_duration": {GAUGE, "Minimum health check duration in Millie seconds"},
"average_duration": {GAUGE, "Average health check duration in Millie seconds"},
},
"pool_processes": {
"pool_pid": {DISCARD, "PID of Pgpool-II child processes"},
"database": {DISCARD, "Database name of the currently active backend connection"},
"pool_pid": {DISCARD, "PID of Pgpool-II child processes"},
"database": {DISCARD, "Database name of the currently active backend connection"},
},
"pool_cache": {
"cache_hit_ratio": {GAUGE, "Query cache hit ratio"},
"num_hash_entries": {GAUGE, "Number of total hash entries"},
"used_hash_entries": {GAUGE, "Number of used hash entries"},
"num_cache_entries": {GAUGE, "Number of used cache entries"},
"used_cache_entries_size": {GAUGE, "Total size of used cache size"},
"free_cache_entries_size": {GAUGE, "Total size of free cache size"},
"cache_hit_ratio": {GAUGE, "Query cache hit ratio"},
"num_hash_entries": {GAUGE, "Number of total hash entries"},
"used_hash_entries": {GAUGE, "Number of used hash entries"},
"num_cache_entries": {GAUGE, "Number of used cache entries"},
"used_cache_entries_size": {GAUGE, "Total size of used cache size"},
"free_cache_entries_size": {GAUGE, "Total size of free cache size"},
},
}
)
Expand Down Expand Up @@ -300,6 +299,7 @@ func queryNamespaceMapping(ch chan<- prometheus.Metric, db *sql.DB, namespace st

// Read from the result of "SHOW pool_processes"
if namespace == "pool_processes" {
frontendByUserDb := make(map[string]map[string]int)
var frontend_total float64
var frontend_used float64

Expand All @@ -310,12 +310,37 @@ func queryNamespaceMapping(ch chan<- prometheus.Metric, db *sql.DB, namespace st
}
frontend_total++
// Loop over column names to find currently connected backend database
var valueDatabase string
var valueUsername string
for idx, columnName := range columnNames {
if columnName == "database" {
if valueDatabase, _ := dbToString(columnData[idx]); len(valueDatabase) != 0 {
frontend_used++
}
switch columnName {
case "database":
valueDatabase, _ = dbToString(columnData[idx])
case "username":
valueUsername, _ = dbToString(columnData[idx])
}
}
if len(valueDatabase) > 0 && len(valueUsername) > 0 {
frontend_used++
dbCount, ok := frontendByUserDb[valueUsername]
if !ok {
dbCount = map[string]int{valueDatabase: 0}
}
dbCount[valueDatabase]++
frontendByUserDb[valueUsername] = dbCount
}
}

variableLabels := []string{"username", "database"}
for userName, dbs := range frontendByUserDb {
for dbName, count := range dbs {
labels := []string{userName, dbName}
ch <- prometheus.MustNewConstMetric(
prometheus.NewDesc(prometheus.BuildFQName("pgpool2", "", "frontend_used"), "Number of used child processes", variableLabels, nil),
prometheus.GaugeValue,
float64(count),
labels...,
)
}
}

Expand All @@ -326,9 +351,9 @@ func queryNamespaceMapping(ch chan<- prometheus.Metric, db *sql.DB, namespace st
frontend_total,
)
ch <- prometheus.MustNewConstMetric(
prometheus.NewDesc(prometheus.BuildFQName("pgpool2", "", "frontend_used"), "Number of used child processes", nil, nil),
prometheus.NewDesc(prometheus.BuildFQName("pgpool2", "", "frontend_used_ratio"), "Ratio of child processes to total processes", nil, nil),
prometheus.GaugeValue,
frontend_used,
frontend_used/frontend_total,
)

return nonfatalErrors, nil
Expand Down Expand Up @@ -473,9 +498,9 @@ func dbToString(t interface{}) (string, bool) {
}

// Convert bool to int.
func parseStatusField(value string) (float64) {
func parseStatusField(value string) float64 {
switch value {
case "true", "up", "waiting":
case "true", "up", "waiting":
return 1.0
case "false", "unused", "down":
return 0.0
Expand Down