Slow query logging

src/config/config.go.example

@@ -23,6 +23,7 @@ var Config = HMNConfig{
 		LogLevel: tracelog.LogLevelError, // LogLevelWarn is recommended for production
 		MinConn:  2, // Keep these low for dev, high for production
 		MaxConn:  10,
+		SlowQueryThresholdMs: 200,
 	},
 	Auth: AuthConfig{
 		CookieDomain: ".handmade.local",

src/config/types.go

@@ -37,14 +37,15 @@ type HMNConfig struct {
 }
 
 type PostgresConfig struct {
-	User     string
-	Password string
-	Hostname string
-	Port     int
-	DbName   string
-	LogLevel tracelog.LogLevel
-	MinConn  int32
-	MaxConn  int32
+	User                 string
+	Password             string
+	Hostname             string
+	Port                 int
+	DbName               string
+	LogLevel             tracelog.LogLevel
+	MinConn              int32
+	MaxConn              int32
+	SlowQueryThresholdMs int
 }
 
 type AuthConfig struct {

src/db/db.go

@@ -7,6 +7,7 @@ import (
 	"reflect"
 	"regexp"
 	"strings"
+	"time"
 
 	"git.handmade.network/hmn/hmn/src/config"
 	"git.handmade.network/hmn/hmn/src/logging"
@@ -298,6 +299,7 @@ func QueryIterator[T any](
 
 	compiled := compileQuery(query, destType)
 
+	queryStart := time.Now()
 	rows, err := conn.Query(ctx, compiled.query, args...)
 	if err != nil {
 		if errors.Is(err, context.DeadlineExceeded) {
@@ -305,6 +307,14 @@ func QueryIterator[T any](
 		}
 		return nil, err
 	}
+	duration := time.Now().Sub(queryStart)
+	if config.Config.Postgres.SlowQueryThresholdMs > 0 && duration > time.Duration(config.Config.Postgres.SlowQueryThresholdMs)*time.Millisecond {
+		logging.Warn().
+			Interface("Duration", duration.String()).
+			Interface("Query", strings.ReplaceAll(strings.ReplaceAll(compiled.query, "\n", " "), "\t", " ")).
+			Interface("Args", args).
+			Msg("Slow query")
+	}
 
 	it := &Iterator[T]{
 		fieldPaths:       compiled.fieldPaths,