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feat: Add wal_status to replication_slot
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Signed-off-by: MarcWort <113890636+MarcWort@users.noreply.github.com>
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@MarcWort
MarcWort committed May 7, 2024
1 parent bbefd10 commit 4e4a729
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Showing 2 changed files with 39 additions and 10 deletions.
30 changes: 28 additions & 2 deletions collector/pg_replication_slot.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,15 @@ var (
"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"}, nil,
)

pgReplicationSlotQuery = `SELECT
slot_name,
Expand All @@ -83,7 +92,8 @@ var (
END AS current_wal_lsn,
COALESCE(confirmed_flush_lsn, '0/0') - '0/0' AS confirmed_flush_lsn,
active,
safe_wal_size
safe_wal_size,
wal_status
FROM pg_replication_slots;`
)

Expand All @@ -103,7 +113,8 @@ func (PGReplicationSlotCollector) Update(ctx context.Context, instance *instance
var flushLSN sql.NullFloat64
var isActive sql.NullBool
var safeWalSize sql.NullInt64
if err := rows.Scan(&slotName, &slotType, &walLSN, &flushLSN, &isActive, &safeWalSize); err != nil {
var walStatus sql.NullString
if err := rows.Scan(&slotName, &slotType, &walLSN, &flushLSN, &isActive, &safeWalSize, &walStatus); err != nil {
return err
}

Expand Down Expand Up @@ -149,6 +160,21 @@ func (PGReplicationSlotCollector) Update(ctx context.Context, instance *instance
prometheus.GaugeValue, float64(safeWalSize.Int64), slotNameLabel, slotTypeLabel,
)
}

if walStatus.Valid {
// See https://www.postgresql.org/docs/14/view-pg-replication-slots.html
walStatusMap := map[string]int{
"reserved": 0, // reserved means that the claimed files are within max_wal_size.
"extended": 1, // extended means that max_wal_size is exceeded but the files are still retained, either by the replication slot or by wal_keep_size.
"unreserved": 2, // unreserved means that the slot no longer retains the required WAL files and some of them are to be removed at the next checkpoint. This state can return to reserved or extended.
"lost": 3, // lost means that some required WAL files have been removed and this slot is no longer usable.
}

ch <- prometheus.MustNewConstMetric(
pgReplicationSlotWalStatus,
prometheus.GaugeValue, float64(walStatusMap[walStatus.String]), slotNameLabel, slotTypeLabel,
)
}
}
return rows.Err()
}
19 changes: 11 additions & 8 deletions collector/pg_replication_slot_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,9 +31,9 @@ func TestPgReplicationSlotCollectorActive(t *testing.T) {

inst := &instance{db: db}

columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size"}
columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size", "wal_status"}
rows := sqlmock.NewRows(columns).
AddRow("test_slot", "physical", 5, 3, true, 323906992)
AddRow("test_slot", "physical", 5, 3, true, 323906992, "reserved")
mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)

ch := make(chan prometheus.Metric)
Expand All @@ -51,6 +51,7 @@ func TestPgReplicationSlotCollectorActive(t *testing.T) {
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 3, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 1, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 323906992, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 0, metricType: dto.MetricType_GAUGE},
}

convey.Convey("Metrics comparison", t, func() {
Expand All @@ -73,9 +74,9 @@ func TestPgReplicationSlotCollectorInActive(t *testing.T) {

inst := &instance{db: db}

columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size"}
columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size", "wal_status"}
rows := sqlmock.NewRows(columns).
AddRow("test_slot", "physical", 6, 12, false, -4000)
AddRow("test_slot", "physical", 6, 12, false, -4000, "extended")
mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)

ch := make(chan prometheus.Metric)
Expand All @@ -92,6 +93,7 @@ func TestPgReplicationSlotCollectorInActive(t *testing.T) {
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 6, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 0, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: -4000, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 1, metricType: dto.MetricType_GAUGE},
}

convey.Convey("Metrics comparison", t, func() {
Expand All @@ -115,9 +117,9 @@ func TestPgReplicationSlotCollectorActiveNil(t *testing.T) {

inst := &instance{db: db}

columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size"}
columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size", "wal_status"}
rows := sqlmock.NewRows(columns).
AddRow("test_slot", "physical", 6, 12, nil, nil)
AddRow("test_slot", "physical", 6, 12, nil, nil, "lost")
mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)

ch := make(chan prometheus.Metric)
Expand All @@ -133,6 +135,7 @@ func TestPgReplicationSlotCollectorActiveNil(t *testing.T) {
expected := []MetricResult{
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 6, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 0, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"slot_name": "test_slot", "slot_type": "physical"}, value: 3, metricType: dto.MetricType_GAUGE},
}

convey.Convey("Metrics comparison", t, func() {
Expand All @@ -155,9 +158,9 @@ func TestPgReplicationSlotCollectorTestNilValues(t *testing.T) {

inst := &instance{db: db}

columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size"}
columns := []string{"slot_name", "slot_type", "current_wal_lsn", "confirmed_flush_lsn", "active", "safe_wal_size", "wal_status"}
rows := sqlmock.NewRows(columns).
AddRow(nil, nil, nil, nil, true, nil)
AddRow(nil, nil, nil, nil, true, nil, nil)
mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)

ch := make(chan prometheus.Metric)
Expand Down

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