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Files
postgres_exporter/collector/pg_stat_walreceiver_test.go
Slavi Pantaleev ef2736e7a6 Fix swapped flushedLsn and receiveStartTli for wal_receiver collector (#1198)
In `pgStatWalReceiverQueryTemplate`, the order of the columns (when `hasFlushedLSN == true`) is:

- ...
- `receive_start_lsn`
- `flushed_lsn`
- `receive_start_tli`
- ...

However, columns were scanned in this order:

- ...
- `receive_start_lsn` -> `receiveStartLsn`
- `receive_start_tli` -> `flushedLsn` (!)
- `flushed_lsn` -> `receiveStartTli` (!)
- ...

This incorrect hydration of variables also manifests as swapped values for the
`pg_stat_wal_receiver_flushed_lsn` and `pg_stat_wal_receiver_receive_start_tli` metrics.

This seems to be a bug that has existed since the initial implementation:

- 2d7e152751
- https://github.com/prometheus-community/postgres_exporter/pull/844

In this patch, I'm:

- fixing the `.Scan()`, so that it hydrates variables in the correct order

- adjusting the order in which metrics are pushed out to the channel,
  to follow the order we consume them in
  (.., `receive_start_lsn`, `flushed_lsn`, `receive_start_tli`, ..)

- adjusting the walreceiver tests, to follow the new order (which matches .`Scan()`)

- fixing a small identation issue in `pgStatWalReceiverQueryTemplate`

Signed-off-by: Slavi Pantaleev <slavi@devture.com>
2025-09-29 18:15:17 +02:00

187 lines
6.4 KiB
Go

// 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"
"fmt"
"testing"
"github.com/DATA-DOG/go-sqlmock"
"github.com/prometheus/client_golang/prometheus"
dto "github.com/prometheus/client_model/go"
"github.com/smartystreets/goconvey/convey"
)
var queryWithFlushedLSN = fmt.Sprintf(pgStatWalReceiverQueryTemplate, "(flushed_lsn - '0/0') % (2^52)::bigint as flushed_lsn,\n")
var queryWithNoFlushedLSN = fmt.Sprintf(pgStatWalReceiverQueryTemplate, "")
func TestPGStatWalReceiverCollectorWithFlushedLSN(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
}
defer db.Close()
inst := &instance{db: db}
infoSchemaColumns := []string{
"column_name",
}
infoSchemaRows := sqlmock.NewRows(infoSchemaColumns).
AddRow(
"flushed_lsn",
)
mock.ExpectQuery(sanitizeQuery(pgStatWalColumnQuery)).WillReturnRows(infoSchemaRows)
columns := []string{
"upstream_host",
"slot_name",
"status",
"receive_start_lsn",
"flushed_lsn",
"receive_start_tli",
"received_tli",
"last_msg_send_time",
"last_msg_receipt_time",
"latest_end_lsn",
"latest_end_time",
"upstream_node",
}
rows := sqlmock.NewRows(columns).
AddRow(
"foo",
"bar",
"stopping",
int64(1200668684563608),
int64(1200668684563609),
1687321285,
1687321280,
1687321275,
1687321276,
int64(1200668684563610),
1687321277,
5,
)
mock.ExpectQuery(sanitizeQuery(queryWithFlushedLSN)).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatWalReceiverCollector{}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PgStatWalReceiverCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1200668684563608, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1200668684563609, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1687321285, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1687321280, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1687321275, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1687321276, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1200668684563610, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 1687321277, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "stopping"}, value: 5, metricType: dto.MetricType_GAUGE},
}
convey.Convey("Metrics comparison", t, func() {
for _, expect := range expected {
m := readMetric(<-ch)
convey.So(expect, convey.ShouldResemble, m)
}
})
if err := mock.ExpectationsWereMet(); err != nil {
t.Errorf("there were unfulfilled exceptions: %s", err)
}
}
func TestPGStatWalReceiverCollectorWithNoFlushedLSN(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
}
defer db.Close()
inst := &instance{db: db}
infoSchemaColumns := []string{
"column_name",
}
infoSchemaRows := sqlmock.NewRows(infoSchemaColumns)
mock.ExpectQuery(sanitizeQuery(pgStatWalColumnQuery)).WillReturnRows(infoSchemaRows)
columns := []string{
"upstream_host",
"slot_name",
"status",
"receive_start_lsn",
"receive_start_tli",
"received_tli",
"last_msg_send_time",
"last_msg_receipt_time",
"latest_end_lsn",
"latest_end_time",
"upstream_node",
}
rows := sqlmock.NewRows(columns).
AddRow(
"foo",
"bar",
"starting",
int64(1200668684563608),
1687321285,
1687321280,
1687321275,
1687321276,
int64(1200668684563610),
1687321277,
5,
)
mock.ExpectQuery(sanitizeQuery(queryWithNoFlushedLSN)).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatWalReceiverCollector{}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PgStatWalReceiverCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1200668684563608, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1687321285, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1687321280, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1687321275, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1687321276, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1200668684563610, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 1687321277, metricType: dto.MetricType_COUNTER},
{labels: labelMap{"upstream_host": "foo", "slot_name": "bar", "status": "starting"}, value: 5, metricType: dto.MetricType_GAUGE},
}
convey.Convey("Metrics comparison", t, func() {
for _, expect := range expected {
m := readMetric(<-ch)
convey.So(expect, convey.ShouldResemble, m)
}
})
if err := mock.ExpectationsWereMet(); err != nil {
t.Errorf("there were unfulfilled exceptions: %s", err)
}
}