pangolin_exporter

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// Copyright 2023 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collector
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import (
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	"context"
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	"database/sql"
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	"github.com/go-kit/log"
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	"github.com/prometheus/client_golang/prometheus"
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)
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func init() {
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	registerCollector(statioUserIndexesSubsystem, defaultDisabled, NewPGStatioUserIndexesCollector)
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}
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type PGStatioUserIndexesCollector struct {
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	log log.Logger
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}
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const statioUserIndexesSubsystem = "statio_user_indexes"
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func NewPGStatioUserIndexesCollector(config collectorConfig) (Collector, error) {
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	return &PGStatioUserIndexesCollector{log: config.logger}, nil
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}
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var (
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	statioUserIndexesIdxBlksRead = prometheus.NewDesc(
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		prometheus.BuildFQName(namespace, statioUserIndexesSubsystem, "idx_blks_read_total"),
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		"Number of disk blocks read from this index",
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		[]string{"schemaname", "relname", "indexrelname"},
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		prometheus.Labels{},
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	)
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	statioUserIndexesIdxBlksHit = prometheus.NewDesc(
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		prometheus.BuildFQName(namespace, statioUserIndexesSubsystem, "idx_blks_hit_total"),
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		"Number of buffer hits in this index",
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		[]string{"schemaname", "relname", "indexrelname"},
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		prometheus.Labels{},
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	)
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	statioUserIndexesQuery = `
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	SELECT
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		schemaname,
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		relname,
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		indexrelname,
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		idx_blks_read,
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		idx_blks_hit
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	FROM pg_statio_user_indexes
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	`
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)
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func (c *PGStatioUserIndexesCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
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	db := instance.getDB()
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	rows, err := db.QueryContext(ctx,
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		statioUserIndexesQuery)
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	if err != nil {
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		return err
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	}
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	defer rows.Close()
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	for rows.Next() {
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		var schemaname, relname, indexrelname sql.NullString
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		var idxBlksRead, idxBlksHit sql.NullFloat64
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		if err := rows.Scan(&schemaname, &relname, &indexrelname, &idxBlksRead, &idxBlksHit); err != nil {
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			return err
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		}
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		schemanameLabel := "unknown"
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		if schemaname.Valid {
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			schemanameLabel = schemaname.String
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		}
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		relnameLabel := "unknown"
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		if relname.Valid {
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			relnameLabel = relname.String
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		}
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		indexrelnameLabel := "unknown"
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		if indexrelname.Valid {
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			indexrelnameLabel = indexrelname.String
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		}
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		labels := []string{schemanameLabel, relnameLabel, indexrelnameLabel}
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		idxBlksReadMetric := 0.0
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		if idxBlksRead.Valid {
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			idxBlksReadMetric = idxBlksRead.Float64
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		}
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		ch <- prometheus.MustNewConstMetric(
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			statioUserIndexesIdxBlksRead,
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			prometheus.CounterValue,
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			idxBlksReadMetric,
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			labels...,
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		)
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		idxBlksHitMetric := 0.0
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		if idxBlksHit.Valid {
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			idxBlksHitMetric = idxBlksHit.Float64
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		}
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		ch <- prometheus.MustNewConstMetric(
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			statioUserIndexesIdxBlksHit,
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			prometheus.CounterValue,
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			idxBlksHitMetric,
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			labels...,
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		)
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	}
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	if err := rows.Err(); err != nil {
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		return err
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	}
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	return nil
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}
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