mirror of
https://github.com/prometheus-community/postgres_exporter
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74800f483a
* Xlog location collector and test Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Add more escapes Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Change to Gauge Signed-off-by: Felix Yuan <felix.yuan@reddit.com> --------- Signed-off-by: Felix Yuan <felix.yuan@reddit.com>
81 lines
2.0 KiB
Go
81 lines
2.0 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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"github.com/go-kit/log"
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"github.com/prometheus/client_golang/prometheus"
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)
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const xlogLocationSubsystem = "xlog_location"
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func init() {
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registerCollector(xlogLocationSubsystem, defaultDisabled, NewPGXlogLocationCollector)
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}
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type PGXlogLocationCollector struct {
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log log.Logger
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}
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func NewPGXlogLocationCollector(config collectorConfig) (Collector, error) {
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return &PGXlogLocationCollector{log: config.logger}, nil
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}
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var (
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xlogLocationBytes = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, xlogLocationSubsystem, "bytes"),
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"Postgres LSN (log sequence number) being generated on primary or replayed on replica (truncated to low 52 bits)",
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[]string{},
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prometheus.Labels{},
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)
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xlogLocationQuery = `
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SELECT CASE
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WHEN pg_is_in_recovery() THEN (pg_last_xlog_replay_location() - '0/0') % (2^52)::bigint
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ELSE (pg_current_xlog_location() - '0/0') % (2^52)::bigint
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END AS bytes
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`
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)
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func (PGXlogLocationCollector) 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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xlogLocationQuery)
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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 bytes float64
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if err := rows.Scan(&bytes); err != nil {
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return err
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}
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ch <- prometheus.MustNewConstMetric(
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xlogLocationBytes,
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prometheus.GaugeValue,
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bytes,
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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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