ab33346cbd
The intent is to use the instance struct to hold the connection to the database as well as metadata about the instance. Currently this metadata only includes the version of postgres for the instance which can be used in the collectors to decide what query to run. In the future this could hold more metadata but for now it keeps the Collector interface arguments to a reasonable number. Signed-off-by: Joe Adams <github@joeadams.io>
107 lines
2.9 KiB
Go
107 lines
2.9 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 processIdleSubsystem = "process_idle"
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func init() {
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registerCollector(processIdleSubsystem, defaultEnabled, NewPGProcessIdleCollector)
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}
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type PGProcessIdleCollector struct {
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log log.Logger
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}
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func NewPGProcessIdleCollector(config collectorConfig) (Collector, error) {
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return &PGProcessIdleCollector{log: config.logger}, nil
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}
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var pgProcessIdleSeconds = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, processIdleSubsystem, "seconds"),
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"Idle time of server processes",
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[]string{"application_name"},
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prometheus.Labels{},
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)
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func (PGProcessIdleCollector) 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,
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`WITH
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metrics AS (
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SELECT
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application_name,
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SUM(EXTRACT(EPOCH FROM (CURRENT_TIMESTAMP - state_change))::bigint)::float AS process_idle_seconds_sum,
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COUNT(*) AS process_idle_seconds_count
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FROM pg_stat_activity
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WHERE state = 'idle'
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GROUP BY application_name
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),
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buckets AS (
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SELECT
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application_name,
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le,
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SUM(
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CASE WHEN EXTRACT(EPOCH FROM (CURRENT_TIMESTAMP - state_change)) <= le
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THEN 1
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ELSE 0
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END
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)::bigint AS bucket
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FROM
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pg_stat_activity,
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UNNEST(ARRAY[1, 2, 5, 15, 30, 60, 90, 120, 300]) AS le
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GROUP BY application_name, le
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ORDER BY application_name, le
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)
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SELECT
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application_name,
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process_idle_seconds_sum as seconds_sum,
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process_idle_seconds_count as seconds_count,
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ARRAY_AGG(le) AS seconds,
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ARRAY_AGG(bucket) AS seconds_bucket
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FROM metrics JOIN buckets USING (application_name)
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GROUP BY 1, 2, 3;`)
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var applicationName string
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var secondsSum int64
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var secondsCount uint64
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var seconds []int64
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var secondsBucket []uint64
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err := row.Scan(&applicationName, &secondsSum, &secondsCount, &seconds, &secondsBucket)
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var buckets = make(map[float64]uint64, len(seconds))
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for i, second := range seconds {
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if i >= len(secondsBucket) {
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break
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}
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buckets[float64(second)] = secondsBucket[i]
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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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ch <- prometheus.MustNewConstHistogram(
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pgProcessIdleSeconds,
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secondsCount, float64(secondsSum), buckets,
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applicationName,
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)
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return nil
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}
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