perf: 提升后端高并发承载能力

backend/internal/db/db.go

@@ -3,6 +3,7 @@ package db
 import (
 	"log"
 	"os"
+	"runtime"
 	"time"
 
 	"gorm.io/driver/sqlite"
@@ -37,15 +38,32 @@ func InitDB() {
 		log.Fatalf("Failed to connect database: %v", err)
 	}
 
-	// Configure connection pool settings
 	sqlDB, err := DB.DB()
 	if err != nil {
 		log.Fatalf("Failed to get database instance: %v", err)
 	}
-	sqlDB.SetMaxOpenConns(10)
-	sqlDB.SetMaxIdleConns(5)
+	maxOpen := runtime.NumCPU()*2 + 1
+	if maxOpen < 4 {
+		maxOpen = 4
+	}
+	if maxOpen > 32 {
+		maxOpen = 32
+	}
+	sqlDB.SetMaxOpenConns(maxOpen)
+	sqlDB.SetMaxIdleConns(maxOpen)
+	sqlDB.SetConnMaxIdleTime(10 * time.Minute)
 	sqlDB.SetConnMaxLifetime(time.Hour)
 
+	for _, pragma := range []string{
+		"PRAGMA synchronous=NORMAL",
+		"PRAGMA temp_store=MEMORY",
+		"PRAGMA foreign_keys=ON",
+	} {
+		if execErr := DB.Exec(pragma).Error; execErr != nil {
+			log.Fatalf("Failed to apply %s: %v", pragma, execErr)
+		}
+	}
+
 	// Auto-migrate the schema
 	err = DB.AutoMigrate(&model.User{}, &model.Room{})
 	if err != nil {
@@ -57,7 +75,7 @@ func InitDB() {
 
 	ensureAdminUser()
 
-	monitor.Infof("Database initialized successfully with WAL mode and connection pooling")
+	monitor.Infof("Database initialized successfully with WAL mode and tuned SQLite pragmas")
 }
 
 func ensureAdminUser() {
@@ -77,14 +95,17 @@ func ensureAdminUser() {
 		updates := map[string]interface{}{}
 		if user.Role != "admin" {
 			updates["role"] = "admin"
+			user.Role = "admin"
 		}
 		if !user.Enabled {
 			updates["enabled"] = true
+			user.Enabled = true
 		}
 		if len(updates) > 0 {
 			DB.Model(&user).Updates(updates)
 			monitor.Warnf("Admin account normalized for username=%s", adminUsername)
 		}
+		cacheUser(user)
 		return
 	}
 
@@ -115,5 +136,10 @@ func ensureAdminUser() {
 		monitor.Warnf("Failed to create default admin room: %v", roomErr)
 	}
 
+	cacheUser(newAdmin)
+	if room.ID != 0 {
+		cacheRoom(room)
+	}
+
 	monitor.Warnf("Default admin created for username=%s; change the password after first login", adminUsername)
 }