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Add support for pg_stat_checkpointer
See: https://www.dbi-services.com/blog/postgresql-17-new-catalog-view-pg_stat_checkpointer/ Signed-off-by: Nicolas Rodriguez <[email protected]>
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‎collector/pg_stat_checkpointer.go

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// Copyright 2021 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/prometheus/client_golang/prometheus"
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)
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const statCheckpointerSubsystem = "stat_checkpointer"
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func init() {
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registerCollector(statCheckpointerSubsystem, defaultEnabled, NewPGStatCheckpointerCollector)
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}
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type PGStatCheckpointerCollector struct {
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}
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func NewPGStatCheckpointerCollector(collectorConfig) (Collector, error) {
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return &PGStatCheckpointerCollector{}, nil
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}
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var (
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statCheckpointerNumTimedDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "num_timed_total"),
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"Number of scheduled checkpoints due to timeout",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerNumRequestedDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "num_requested_total"),
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"Number of requested checkpoints that have been performed",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerRestartpointsTimedDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "restartpoints_timed_total"),
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"Number of scheduled restartpoints due to timeout or after a failed attempt to perform it",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerRestartpointsReqDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "restartpoints_req_total"),
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"Number of requested restartpoints",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerRestartpointsDoneDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "restartpoints_done_total"),
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"Number of restartpoints that have been performed",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerWriteTimeDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "write_time_total"),
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"Total amount of time that has been spent in the portion of processing checkpoints and restartpoints where files are written to disk, in milliseconds",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerSyncTimeDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "sync_time_total"),
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"Total amount of time that has been spent in the portion of processing checkpoints and restartpoints where files are synchronized to disk, in milliseconds",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerBuffersWrittenDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "buffers_written_total"),
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"Number of buffers written during checkpoints and restartpoints",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerStatsResetDesc = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, statCheckpointerSubsystem, "stats_reset_total"),
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"Time at which these statistics were last reset",
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[]string{},
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prometheus.Labels{},
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)
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statCheckpointerQuery = `SELECT
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num_timed
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,num_requested
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,restartpoints_timed
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,restartpoints_req
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,restartpoints_done
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,write_time
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,sync_time
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,buffers_written
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,stats_reset
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FROM pg_stat_checkpointer;`
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)
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func (PGStatCheckpointerCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
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db := instance.getDB()
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row := db.QueryRowContext(ctx, statCheckpointerQuery)
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// num_timed = nt = bigint
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// num_requested = nr = bigint
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// restartpoints_timed = rpt = bigint
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// restartpoints_req = rpr = bigint
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// restartpoints_done = rpd = bigint
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// write_time = wt = double precision
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// sync_time = st = double precision
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// buffers_written = bw = bigint
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// stats_reset = sr = timestamp
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var nt, nr, rpt, rpr, rpd, bw sql.NullInt64
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var wt, st sql.NullFloat64
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var sr sql.NullTime
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err := row.Scan(&nt, &nr, &rpt, &rpr, &rpd, &wt, &st, &bw, &sr)
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if err != nil {
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return err
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}
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ntMetric := 0.0
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if nt.Valid {
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ntMetric = float64(nt.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerNumTimedDesc,
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prometheus.CounterValue,
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ntMetric,
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)
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nrMetric := 0.0
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if nr.Valid {
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nrMetric = float64(nr.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerNumRequestedDesc,
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prometheus.CounterValue,
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nrMetric,
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)
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rptMetric := 0.0
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if rpt.Valid {
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rptMetric = float64(rpt.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerRestartpointsTimedDesc,
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prometheus.CounterValue,
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rptMetric,
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)
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rprMetric := 0.0
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if rpr.Valid {
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rprMetric = float64(rpr.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerRestartpointsReqDesc,
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prometheus.CounterValue,
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rprMetric,
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)
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rpdMetric := 0.0
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if rpd.Valid {
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rpdMetric = float64(rpd.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerRestartpointsDoneDesc,
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prometheus.CounterValue,
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rpdMetric,
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)
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wtMetric := 0.0
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if wt.Valid {
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wtMetric = float64(wt.Float64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerWriteTimeDesc,
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prometheus.CounterValue,
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wtMetric,
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)
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stMetric := 0.0
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if st.Valid {
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stMetric = float64(st.Float64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerSyncTimeDesc,
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prometheus.CounterValue,
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stMetric,
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)
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bwMetric := 0.0
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if bw.Valid {
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bwMetric = float64(bw.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerBuffersWrittenDesc,
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prometheus.CounterValue,
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bwMetric,
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)
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srMetric := 0.0
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if sr.Valid {
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srMetric = float64(sr.Time.Unix())
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}
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ch <- prometheus.MustNewConstMetric(
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statCheckpointerStatsResetDesc,
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prometheus.CounterValue,
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srMetric,
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)
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return nil
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}

‎collector/pg_stat_checkpointer_test.go

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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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"testing"
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"time"
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"github.com/DATA-DOG/go-sqlmock"
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"github.com/prometheus/client_golang/prometheus"
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dto "github.com/prometheus/client_model/go"
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"github.com/smartystreets/goconvey/convey"
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)
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func TestPGStatCheckpointerCollector(t *testing.T) {
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db, mock, err := sqlmock.New()
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if err != nil {
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t.Fatalf("Error opening a stub db connection: %s", err)
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}
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defer db.Close()
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inst := &instance{db: db}
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columns := []string{
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"num_timed",
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"num_requested",
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"restartpoints_timed",
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"restartpoints_req",
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"restartpoints_done",
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"write_time",
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"sync_time",
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"buffers_written",
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"stats_reset"}
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srT, err := time.Parse("2006-01-02 15:04:05.00000-07", "2023-05-25 17:10:42.81132-07")
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if err != nil {
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t.Fatalf("Error parsing time: %s", err)
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}
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rows := sqlmock.NewRows(columns).
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AddRow(354, 4945, 289097744, 1242257, 3275602074, 89320867, 450139, 2034563757, srT)
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mock.ExpectQuery(sanitizeQuery(statCheckpointerQuery)).WillReturnRows(rows)
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ch := make(chan prometheus.Metric)
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go func() {
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defer close(ch)
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c := PGStatCheckpointerCollector{}
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if err := c.Update(context.Background(), inst, ch); err != nil {
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t.Errorf("Error calling PGStatCheckpointerCollector.Update: %s", err)
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}
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}()
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expected := []MetricResult{
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 354},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 4945},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 289097744},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 1242257},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 3275602074},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 89320867},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 450139},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 2034563757},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 1685059842},
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}
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convey.Convey("Metrics comparison", t, func() {
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for _, expect := range expected {
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m := readMetric(<-ch)
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convey.So(expect, convey.ShouldResemble, m)
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}
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})
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if err := mock.ExpectationsWereMet(); err != nil {
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t.Errorf("there were unfulfilled exceptions: %s", err)
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}
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}
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func TestPGStatCheckpointerCollectorNullValues(t *testing.T) {
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db, mock, err := sqlmock.New()
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if err != nil {
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t.Fatalf("Error opening a stub db connection: %s", err)
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}
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defer db.Close()
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inst := &instance{db: db}
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columns := []string{
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"num_timed",
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"num_requested",
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"restartpoints_timed",
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"restartpoints_req",
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"restartpoints_done",
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"write_time",
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"sync_time",
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"buffers_written",
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"stats_reset"}
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rows := sqlmock.NewRows(columns).
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AddRow(nil, nil, nil, nil, nil, nil, nil, nil, nil)
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mock.ExpectQuery(sanitizeQuery(statCheckpointerQuery)).WillReturnRows(rows)
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ch := make(chan prometheus.Metric)
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go func() {
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defer close(ch)
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c := PGStatCheckpointerCollector{}
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if err := c.Update(context.Background(), inst, ch); err != nil {
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t.Errorf("Error calling PGStatCheckpointerCollector.Update: %s", err)
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}
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}()
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expected := []MetricResult{
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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{labels: labelMap{}, metricType: dto.MetricType_COUNTER, value: 0},
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}
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convey.Convey("Metrics comparison", t, func() {
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for _, expect := range expected {
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m := readMetric(<-ch)
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convey.So(expect, convey.ShouldResemble, m)
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}
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})
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if err := mock.ExpectationsWereMet(); err != nil {
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t.Errorf("there were unfulfilled exceptions: %s", err)
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}
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}

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