130 lines
2.8 KiB
Go
130 lines
2.8 KiB
Go
// 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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const locksSubsystem = "locks"
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func init() {
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registerCollector(locksSubsystem, defaultEnabled, NewPGLocksCollector)
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}
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type PGLocksCollector struct {
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log log.Logger
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}
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func NewPGLocksCollector(config collectorConfig) (Collector, error) {
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return &PGLocksCollector{
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log: config.logger,
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}, nil
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}
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var (
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pgLocksDesc = prometheus.NewDesc(
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prometheus.BuildFQName(
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namespace,
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locksSubsystem,
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"count",
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),
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"Number of locks",
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[]string{"datname", "mode"}, nil,
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)
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pgLocksQuery = `
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SELECT
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pg_database.datname as datname,
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tmp.mode as mode,
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COALESCE(count, 0) as count
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FROM
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(
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VALUES
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('accesssharelock'),
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('rowsharelock'),
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('rowexclusivelock'),
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('shareupdateexclusivelock'),
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('sharelock'),
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('sharerowexclusivelock'),
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('exclusivelock'),
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('accessexclusivelock'),
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('sireadlock')
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) AS tmp(mode)
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CROSS JOIN pg_database
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LEFT JOIN (
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SELECT
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database,
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lower(mode) AS mode,
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count(*) AS count
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FROM
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pg_locks
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WHERE
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database IS NOT NULL
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GROUP BY
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database,
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lower(mode)
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) AS tmp2 ON tmp.mode = tmp2.mode
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and pg_database.oid = tmp2.database
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ORDER BY
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1
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`
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)
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// Update implements Collector and exposes database locks.
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// It is called by the Prometheus registry when collecting metrics.
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func (c PGLocksCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
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db := instance.getDB()
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// Query the list of databases
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rows, err := db.QueryContext(ctx,
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pgLocksQuery,
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)
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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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var datname, mode sql.NullString
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var count sql.NullInt64
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for rows.Next() {
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if err := rows.Scan(&datname, &mode, &count); err != nil {
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return err
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}
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if !datname.Valid || !mode.Valid {
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continue
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}
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countMetric := 0.0
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if count.Valid {
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countMetric = float64(count.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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pgLocksDesc,
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prometheus.GaugeValue, countMetric,
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datname.String, mode.String,
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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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