postgres_exporter/collector/pg_statio_user_indexes.go

119 lines
3.1 KiB
Go

// 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"
)
func init() {
registerCollector(statioUserIndexesSubsystem, defaultDisabled, NewPGStatioUserIndexesCollector)
}
type PGStatioUserIndexesCollector struct {
log log.Logger
}
const statioUserIndexesSubsystem = "statio_user_indexes"
func NewPGStatioUserIndexesCollector(config collectorConfig) (Collector, error) {
return &PGStatioUserIndexesCollector{log: config.logger}, nil
}
var (
statioUserIndexesIdxBlksRead = prometheus.NewDesc(
prometheus.BuildFQName(namespace, statioUserIndexesSubsystem, "idx_blks_read_total"),
"Number of disk blocks read from this index",
[]string{"schemaname", "relname", "indexrelname"},
prometheus.Labels{},
)
statioUserIndexesIdxBlksHit = prometheus.NewDesc(
prometheus.BuildFQName(namespace, statioUserIndexesSubsystem, "idx_blks_hit_total"),
"Number of buffer hits in this index",
[]string{"schemaname", "relname", "indexrelname"},
prometheus.Labels{},
)
statioUserIndexesQuery = `
SELECT
schemaname,
relname,
indexrelname,
idx_blks_read,
idx_blks_hit
FROM pg_statio_user_indexes
`
)
func (c *PGStatioUserIndexesCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
db := instance.getDB()
rows, err := db.QueryContext(ctx,
statioUserIndexesQuery)
if err != nil {
return err
}
defer rows.Close()
for rows.Next() {
var schemaname, relname, indexrelname sql.NullString
var idxBlksRead, idxBlksHit sql.NullFloat64
if err := rows.Scan(&schemaname, &relname, &indexrelname, &idxBlksRead, &idxBlksHit); err != nil {
return err
}
schemanameLabel := "unknown"
if schemaname.Valid {
schemanameLabel = schemaname.String
}
relnameLabel := "unknown"
if relname.Valid {
relnameLabel = relname.String
}
indexrelnameLabel := "unknown"
if indexrelname.Valid {
indexrelnameLabel = indexrelname.String
}
labels := []string{schemanameLabel, relnameLabel, indexrelnameLabel}
idxBlksReadMetric := 0.0
if idxBlksRead.Valid {
idxBlksReadMetric = idxBlksRead.Float64
}
ch <- prometheus.MustNewConstMetric(
statioUserIndexesIdxBlksRead,
prometheus.CounterValue,
idxBlksReadMetric,
labels...,
)
idxBlksHitMetric := 0.0
if idxBlksHit.Valid {
idxBlksHitMetric = idxBlksHit.Float64
}
ch <- prometheus.MustNewConstMetric(
statioUserIndexesIdxBlksHit,
prometheus.CounterValue,
idxBlksHitMetric,
labels...,
)
}
if err := rows.Err(); err != nil {
return err
}
return nil
}