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feat: allow setting limit in pg_stat_statements (#1205)

Browse Source 
Add `.limit` CLI flag to `stat_statements` collector to allow
setting a custom number of queries to be returned.

Signed-off-by: Cristian Greco <cristian@regolo.cc>
This commit is contained in:
Cristian Greco
2025-10-08 04:06:13 +02:00
committed by GitHub
parent a95b518a68
commit c70a059071
2 changed files with 216 additions and 25 deletions
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33
collector/pg_stat_statements.go
View File

@@ -24,11 +24,15 @@ import (
"github.com/prometheus/client_golang/prometheus"
)
const statStatementsSubsystem = "stat_statements"
const (
statStatementsSubsystem = "stat_statements"
defaultStatementLimit = "100"
)
var (
includeQueryFlag *bool = nil
statementLengthFlag *uint = nil
statementLimitFlag *uint = nil
)
func init() {
@@ -47,12 +51,18 @@ func init() {
"Maximum length of the statement text.").
Default("120").
Uint()
statementLimitFlag = kingpin.Flag(
fmt.Sprint(collectorFlagPrefix, statStatementsSubsystem, ".limit"),
"Maximum number of statements to return.").
Default(defaultStatementLimit).
Uint()
}
type PGStatStatementsCollector struct {
log *slog.Logger
includeQueryStatement bool
statementLength uint
statementLimit uint
}
func NewPGStatStatementsCollector(config collectorConfig) (Collector, error) {
@@ -60,6 +70,7 @@ func NewPGStatStatementsCollector(config collectorConfig) (Collector, error) {
log: config.logger,
includeQueryStatement: *includeQueryFlag,
statementLength: *statementLengthFlag,
statementLimit: *statementLimitFlag,
}, nil
}
@@ -126,9 +137,9 @@ const (
FROM pg_stat_statements
)
ORDER BY seconds_total DESC
LIMIT 100;`
LIMIT %s;`
pgStatStatementsNewQuery = `SELECT
pgStatStatementsQuery_PG13 = `SELECT
pg_get_userbyid(userid) as user,
pg_database.datname,
pg_stat_statements.queryid,
@@ -148,7 +159,7 @@ const (
FROM pg_stat_statements
)
ORDER BY seconds_total DESC
LIMIT 100;`
LIMIT %s;`
pgStatStatementsQuery_PG17 = `SELECT
pg_get_userbyid(userid) as user,
@@ -170,7 +181,7 @@ const (
FROM pg_stat_statements
)
ORDER BY seconds_total DESC
LIMIT 100;`
LIMIT %s;`
)
func (c PGStatStatementsCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
@@ -179,20 +190,24 @@ func (c PGStatStatementsCollector) Update(ctx context.Context, instance *instanc
case instance.version.GE(semver.MustParse("17.0.0")):
queryTemplate = pgStatStatementsQuery_PG17
case instance.version.GE(semver.MustParse("13.0.0")):
queryTemplate = pgStatStatementsNewQuery
queryTemplate = pgStatStatementsQuery_PG13
default:
queryTemplate = pgStatStatementsQuery
}
var querySelect = ""
querySelect := ""
if c.includeQueryStatement {
querySelect = fmt.Sprintf(pgStatStatementQuerySelect, c.statementLength)
}
query := fmt.Sprintf(queryTemplate, querySelect)
statementLimit := defaultStatementLimit
if c.statementLimit > 0 {
statementLimit = fmt.Sprintf("%d", c.statementLimit)
}
query := fmt.Sprintf(queryTemplate, querySelect, statementLimit)
db := instance.getDB()
rows, err := db.QueryContext(ctx, query)
var presentQueryIds = make(map[string]struct{})
presentQueryIds := make(map[string]struct{})
if err != nil {
return err

208
collector/pg_stat_statements_test.go
View File

@@ -24,7 +24,7 @@ import (
"github.com/smartystreets/goconvey/convey"
)
func TestPGStateStatementsCollector(t *testing.T) {
func TestPGStatStatementsCollector(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -36,7 +36,7 @@ func TestPGStateStatementsCollector(t *testing.T) {
columns := []string{"user", "datname", "queryid", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, ""))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, "", defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -67,7 +67,7 @@ func TestPGStateStatementsCollector(t *testing.T) {
}
}
func TestPGStateStatementsCollectorWithStatement(t *testing.T) {
func TestPGStatStatementsCollectorWithStatement(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -79,7 +79,7 @@ func TestPGStateStatementsCollectorWithStatement(t *testing.T) {
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 100) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, fmt.Sprintf(pgStatStatementQuerySelect, 100)))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, fmt.Sprintf(pgStatStatementQuerySelect, 100), defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -111,7 +111,51 @@ func TestPGStateStatementsCollectorWithStatement(t *testing.T) {
}
}
func TestPGStateStatementsCollectorNull(t *testing.T) {
func TestPGStatStatementsCollectorWithStatementAndLimit(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, version: semver.MustParse("12.0.0")}
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 100) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, fmt.Sprintf(pgStatStatementQuerySelect, 100), "10"))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 100, statementLimit: 10}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 5},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.4},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 100},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.1},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.2},
{labels: labelMap{"queryid": "1500", "query": "select 1 from foo"}, metricType: dto.MetricType_COUNTER, value: 1},
}
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 TestPGStatStatementsCollectorNull(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -123,7 +167,7 @@ func TestPGStateStatementsCollectorNull(t *testing.T) {
columns := []string{"user", "datname", "queryid", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow(nil, nil, nil, nil, nil, nil, nil, nil)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, ""))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, "", defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -154,7 +198,7 @@ func TestPGStateStatementsCollectorNull(t *testing.T) {
}
}
func TestPGStateStatementsCollectorNullWithStatement(t *testing.T) {
func TestPGStatStatementsCollectorNullWithStatement(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -166,7 +210,7 @@ func TestPGStateStatementsCollectorNullWithStatement(t *testing.T) {
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 200) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow(nil, nil, nil, nil, nil, nil, nil, nil, nil)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, fmt.Sprintf(pgStatStatementQuerySelect, 200)))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, fmt.Sprintf(pgStatStatementQuerySelect, 200), defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -198,7 +242,51 @@ func TestPGStateStatementsCollectorNullWithStatement(t *testing.T) {
}
}
func TestPGStateStatementsCollectorNewPG(t *testing.T) {
func TestPGStatStatementsCollectorNullWithStatementAndLimit(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, version: semver.MustParse("13.3.7")}
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 200) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow(nil, nil, nil, nil, nil, nil, nil, nil, nil)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, fmt.Sprintf(pgStatStatementQuerySelect, 200), "10"))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 200, statementLimit: 10}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"user": "unknown", "datname": "unknown", "queryid": "unknown"}, metricType: dto.MetricType_COUNTER, value: 0},
{labels: labelMap{"user": "unknown", "datname": "unknown", "queryid": "unknown"}, metricType: dto.MetricType_COUNTER, value: 0},
{labels: labelMap{"user": "unknown", "datname": "unknown", "queryid": "unknown"}, metricType: dto.MetricType_COUNTER, value: 0},
{labels: labelMap{"user": "unknown", "datname": "unknown", "queryid": "unknown"}, metricType: dto.MetricType_COUNTER, value: 0},
{labels: labelMap{"user": "unknown", "datname": "unknown", "queryid": "unknown"}, metricType: dto.MetricType_COUNTER, value: 0},
{labels: labelMap{"queryid": "unknown", "query": "unknown"}, metricType: dto.MetricType_COUNTER, value: 1},
}
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 TestPGStatStatementsCollector_PG13(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -210,7 +298,7 @@ func TestPGStateStatementsCollectorNewPG(t *testing.T) {
columns := []string{"user", "datname", "queryid", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, ""))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, "", defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -241,7 +329,7 @@ func TestPGStateStatementsCollectorNewPG(t *testing.T) {
}
}
func TestPGStateStatementsCollectorNewPGWithStatement(t *testing.T) {
func TestPGStatStatementsCollector_PG13_WithStatement(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -253,7 +341,7 @@ func TestPGStateStatementsCollectorNewPGWithStatement(t *testing.T) {
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 300) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, fmt.Sprintf(pgStatStatementQuerySelect, 300)))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, fmt.Sprintf(pgStatStatementQuerySelect, 300), defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -285,7 +373,51 @@ func TestPGStateStatementsCollectorNewPGWithStatement(t *testing.T) {
}
}
func TestPGStateStatementsCollector_PG17(t *testing.T) {
func TestPGStatStatementsCollector_PG13_WithStatementAndLimit(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, version: semver.MustParse("13.3.7")}
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 300) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG13, fmt.Sprintf(pgStatStatementQuerySelect, 300), "10"))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 300, statementLimit: 10}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 5},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.4},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 100},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.1},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.2},
{labels: labelMap{"queryid": "1500", "query": "select 1 from foo"}, metricType: dto.MetricType_COUNTER, value: 1},
}
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 TestPGStatStatementsCollector_PG17(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -297,7 +429,7 @@ func TestPGStateStatementsCollector_PG17(t *testing.T) {
columns := []string{"user", "datname", "queryid", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG17, ""))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG17, "", defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -328,7 +460,7 @@ func TestPGStateStatementsCollector_PG17(t *testing.T) {
}
}
func TestPGStateStatementsCollector_PG17_WithStatement(t *testing.T) {
func TestPGStatStatementsCollector_PG17_WithStatement(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("Error opening a stub db connection: %s", err)
@@ -340,7 +472,7 @@ func TestPGStateStatementsCollector_PG17_WithStatement(t *testing.T) {
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 300) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG17, fmt.Sprintf(pgStatStatementQuerySelect, 300)))).WillReturnRows(rows)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG17, fmt.Sprintf(pgStatStatementQuerySelect, 300), defaultStatementLimit))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
@@ -371,3 +503,47 @@ func TestPGStateStatementsCollector_PG17_WithStatement(t *testing.T) {
t.Errorf("there were unfulfilled exceptions: %s", err)
}
}
func TestPGStatStatementsCollector_PG17_WithStatementAndLimit(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, version: semver.MustParse("17.0.0")}
columns := []string{"user", "datname", "queryid", "LEFT(pg_stat_statements.query, 300) as query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
rows := sqlmock.NewRows(columns).
AddRow("postgres", "postgres", 1500, "select 1 from foo", 5, 0.4, 100, 0.1, 0.2)
mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery_PG17, fmt.Sprintf(pgStatStatementQuerySelect, 300), "10"))).WillReturnRows(rows)
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 300, statementLimit: 10}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 5},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.4},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 100},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.1},
{labels: labelMap{"user": "postgres", "datname": "postgres", "queryid": "1500"}, metricType: dto.MetricType_COUNTER, value: 0.2},
{labels: labelMap{"queryid": "1500", "query": "select 1 from foo"}, metricType: dto.MetricType_COUNTER, value: 1},
}
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)
}
}