1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
// Copyright 2023 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package collector
import (
"context"
"database/sql"
"log/slog"
"github.com/blang/semver/v4"
"github.com/prometheus/client_golang/prometheus"
)
const replicationSlotSubsystem = "replication_slot"
func init() {
registerCollector(replicationSlotSubsystem, defaultEnabled, NewPGReplicationSlotCollector)
}
type PGReplicationSlotCollector struct {
log *slog.Logger
}
func NewPGReplicationSlotCollector(config collectorConfig) (Collector, error) {
return &PGReplicationSlotCollector{log: config.logger}, nil
}
var (
pgReplicationSlotCurrentWalDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_current_wal_lsn",
),
"current wal lsn value",
[]string{"slot_name", "slot_type"}, nil,
)
pgReplicationSlotCurrentFlushDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_confirmed_flush_lsn",
),
"last lsn confirmed flushed to the replication slot",
[]string{"slot_name", "slot_type"}, nil,
)
pgReplicationSlotIsActiveDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_is_active",
),
"whether the replication slot is active or not",
[]string{"slot_name", "slot_type"}, nil,
)
pgReplicationSlotSafeWal = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"safe_wal_size_bytes",
),
"number of bytes that can be written to WAL such that this slot is not in danger of getting in state lost",
[]string{"slot_name", "slot_type"}, nil,
)
pgReplicationSlotWalStatus = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"wal_status",
),
"availability of WAL files claimed by this slot",
[]string{"slot_name", "slot_type", "wal_status"}, nil,
)
pgReplicationSlotQuery = `SELECT
slot_name,
slot_type,
CASE WHEN pg_is_in_recovery() THEN
pg_last_wal_receive_lsn() - '0/0'
ELSE
pg_current_wal_lsn() - '0/0'
END AS current_wal_lsn,
COALESCE(confirmed_flush_lsn, '0/0') - '0/0' AS confirmed_flush_lsn,
active
FROM pg_replication_slots;`
pgReplicationSlotNewQuery = `SELECT
slot_name,
slot_type,
CASE WHEN pg_is_in_recovery() THEN
pg_last_wal_receive_lsn() - '0/0'
ELSE
pg_current_wal_lsn() - '0/0'
END AS current_wal_lsn,
COALESCE(confirmed_flush_lsn, '0/0') - '0/0' AS confirmed_flush_lsn,
active,
safe_wal_size,
wal_status
FROM pg_replication_slots;`
)
func (PGReplicationSlotCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
query := pgReplicationSlotQuery
abovePG13 := instance.version.GTE(semver.MustParse("13.0.0"))
if abovePG13 {
query = pgReplicationSlotNewQuery
}
db := instance.getDB()
rows, err := db.QueryContext(ctx,
query)
if err != nil {
return err
}
defer rows.Close()
for rows.Next() {
var slotName sql.NullString
var slotType sql.NullString
var walLSN sql.NullFloat64
var flushLSN sql.NullFloat64
var isActive sql.NullBool
var safeWalSize sql.NullInt64
var walStatus sql.NullString
r := []any{
&slotName,
&slotType,
&walLSN,
&flushLSN,
&isActive,
}
if abovePG13 {
r = append(r, &safeWalSize)
r = append(r, &walStatus)
}
err := rows.Scan(r...)
if err != nil {
return err
}
isActiveValue := 0.0
if isActive.Valid && isActive.Bool {
isActiveValue = 1.0
}
slotNameLabel := "unknown"
if slotName.Valid {
slotNameLabel = slotName.String
}
slotTypeLabel := "unknown"
if slotType.Valid {
slotTypeLabel = slotType.String
}
var walLSNMetric float64
if walLSN.Valid {
walLSNMetric = walLSN.Float64
}
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotCurrentWalDesc,
prometheus.GaugeValue, walLSNMetric, slotNameLabel, slotTypeLabel,
)
if isActive.Valid && isActive.Bool {
var flushLSNMetric float64
if flushLSN.Valid {
flushLSNMetric = flushLSN.Float64
}
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotCurrentFlushDesc,
prometheus.GaugeValue, flushLSNMetric, slotNameLabel, slotTypeLabel,
)
}
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotIsActiveDesc,
prometheus.GaugeValue, isActiveValue, slotNameLabel, slotTypeLabel,
)
if safeWalSize.Valid {
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotSafeWal,
prometheus.GaugeValue, float64(safeWalSize.Int64), slotNameLabel, slotTypeLabel,
)
}
if walStatus.Valid {
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotWalStatus,
prometheus.GaugeValue, 1, slotNameLabel, slotTypeLabel, walStatus.String,
)
}
}
return rows.Err()
}
|
