Dynamic statement length.

Author: Jakub Štiller

collector/collector.go

@@ -38,8 +38,9 @@ const (
 	// Namespace for all metrics.
 	namespace = "pg"
 
-	defaultEnabled  = true
-	defaultDisabled = false
+	collectorFlagPrefix = "collector."
+	defaultEnabled      = true
+	defaultDisabled     = false
 )
 
 var (
@@ -75,7 +76,7 @@ func registerCollector(name string, isDefaultEnabled bool, createFunc func(colle
 	}
 
 	// Create flag for this collector
-	flagName := fmt.Sprintf("collector.%s", name)
+	flagName := fmt.Sprint(collectorFlagPrefix, name)
 	flagHelp := fmt.Sprintf("Enable the %s collector (default: %s).", name, helpDefaultState)
 	defaultValue := fmt.Sprintf("%v", isDefaultEnabled)
 

collector/pg_stat_statements.go

@@ -25,29 +25,40 @@ import (
 
 const statStatementsSubsystem = "stat_statements"
 
-var includeQueryFlag *bool = nil
+var (
+	includeQueryFlag    *bool = nil
+	statementLengthFlag *uint = nil
+)
 
 func init() {
 	// WARNING:
 	//   Disabled by default because this set of metrics can be quite expensive on a busy server
 	//   Every unique query will cause a new timeseries to be created
 	registerCollector(statStatementsSubsystem, defaultDisabled, NewPGStatStatementsCollector)
 
-	flagName := fmt.Sprintf("collector.%s.include_query", statStatementsSubsystem)
-	flagHelp := "Enable selecting statement query together with queryId. (default: false)"
-	defaultValue := fmt.Sprintf("%v", defaultDisabled)
-	includeQueryFlag = kingpin.Flag(flagName, flagHelp).Default(defaultValue).Bool()
+	includeQueryFlag = kingpin.Flag(
+		fmt.Sprint(collectorFlagPrefix, statStatementsSubsystem, ".include_query"),
+		"Enable selecting statement query together with queryId. (default: disabled)").
+		Default(fmt.Sprintf("%v", defaultDisabled)).
+		Bool()
+	statementLengthFlag = kingpin.Flag(
+		fmt.Sprint(collectorFlagPrefix, statStatementsSubsystem, ".query_length"),
+		"Maximum length of the statement text.").
+		Default("120").
+		Uint()
 }
 
 type PGStatStatementsCollector struct {
 	log                   log.Logger
 	includeQueryStatement bool
+	statementLength       uint
 }
 
 func NewPGStatStatementsCollector(config collectorConfig) (Collector, error) {
 	return &PGStatStatementsCollector{
 		log:                   config.logger,
 		includeQueryStatement: *includeQueryFlag,
+		statementLength:       *statementLengthFlag,
 	}, nil
 }
 
@@ -89,8 +100,10 @@ var (
 		[]string{"queryid", "query"},
 		prometheus.Labels{},
 	)
+)
 
-	pgStatStatementQuerySelect = "LEFT(pg_stat_statements.query, 120) as query,"
+const (
+	pgStatStatementQuerySelect = `LEFT(pg_stat_statements.query, %d) as query,`
 
 	pgStatStatementsQuery = `SELECT
 		pg_get_userbyid(userid) as user,
@@ -144,7 +157,7 @@ func (c PGStatStatementsCollector) Update(ctx context.Context, instance *instanc
 	}
 	var querySelect = ""
 	if c.includeQueryStatement {
-		querySelect = pgStatStatementQuerySelect
+		querySelect = fmt.Sprintf(pgStatStatementQuerySelect, c.statementLength)
 	}
 	query := fmt.Sprintf(queryTemplate, querySelect)
 

collector/pg_stat_statements_test.go

@@ -76,15 +76,15 @@ func TestPGStateStatementsCollectorWithStatement(t *testing.T) {
 
 	inst := &instance{db: db, version: semver.MustParse("12.0.0")}
 
-	columns := []string{"user", "datname", "queryid", "query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
+	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, pgStatStatementQuerySelect))).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsQuery, fmt.Sprintf(pgStatStatementQuerySelect, 100)))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
 		defer close(ch)
-		c := PGStatStatementsCollector{includeQueryStatement: true}
+		c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 100}
 
 		if err := c.Update(context.Background(), inst, ch); err != nil {
 			t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
@@ -163,15 +163,15 @@ func TestPGStateStatementsCollectorNullWithStatement(t *testing.T) {
 
 	inst := &instance{db: db, version: semver.MustParse("13.3.7")}
 
-	columns := []string{"user", "datname", "queryid", "query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
+	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, pgStatStatementQuerySelect))).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, fmt.Sprintf(pgStatStatementQuerySelect, 200)))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
 		defer close(ch)
-		c := PGStatStatementsCollector{includeQueryStatement: true}
+		c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 200}
 
 		if err := c.Update(context.Background(), inst, ch); err != nil {
 			t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)
@@ -250,15 +250,15 @@ func TestPGStateStatementsCollectorNewPGWithStatement(t *testing.T) {
 
 	inst := &instance{db: db, version: semver.MustParse("13.3.7")}
 
-	columns := []string{"user", "datname", "queryid", "query", "calls_total", "seconds_total", "rows_total", "block_read_seconds_total", "block_write_seconds_total"}
+	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, pgStatStatementQuerySelect))).WillReturnRows(rows)
+	mock.ExpectQuery(sanitizeQuery(fmt.Sprintf(pgStatStatementsNewQuery, fmt.Sprintf(pgStatStatementQuerySelect, 300)))).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {
 		defer close(ch)
-		c := PGStatStatementsCollector{includeQueryStatement: true}
+		c := PGStatStatementsCollector{includeQueryStatement: true, statementLength: 300}
 
 		if err := c.Update(context.Background(), inst, ch); err != nil {
 			t.Errorf("Error calling PGStatStatementsCollector.Update: %s", err)