perf(后端): 完成性能优化与连接池配置

新增 DB/Redis 连接池配置与校验，并补充单测网关请求体大小限制与 413 处理 HTTP/req 客户端池化并调整上游连接池默认值并发槽位改为 ZSET+Lua 与指数退避用量统计改 SQL 聚合并新增索引迁移计费缓存写入改工作池并补测试/基准测试: 在 backend/ 下运行 go test ./...
2025-12-31 08:50:12 +08:00
parent 5376786694
commit 7efa8b54c4
53 changed files with 1805 additions and 449 deletions
--- a/backend/cmd/server/wire.go
+++ b/backend/cmd/server/wire.go
@@ -67,6 +67,7 @@ func provideCleanup(
 	tokenRefresh *service.TokenRefreshService,
 	pricing *service.PricingService,
 	emailQueue *service.EmailQueueService,
+	billingCache *service.BillingCacheService,
 	oauth *service.OAuthService,
 	openaiOAuth *service.OpenAIOAuthService,
 	geminiOAuth *service.GeminiOAuthService,
@@ -94,6 +95,10 @@ func provideCleanup(
 				emailQueue.Stop()
 				return nil
 			}},
+			{"BillingCacheService", func() error {
+				billingCache.Stop()
+				return nil
+			}},
 			{"OAuthService", func() error {
 				oauth.Stop()
 				return nil
--- a/backend/cmd/server/wire_gen.go
+++ b/backend/cmd/server/wire_gen.go
@@ -39,11 +39,11 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	if err != nil {
 		return nil, err
 	}
-	sqlDB, err := infrastructure.ProvideSQLDB(client)
+	db, err := infrastructure.ProvideSQLDB(client)
 	if err != nil {
 		return nil, err
 	}
-	userRepository := repository.NewUserRepository(client, sqlDB)
+	userRepository := repository.NewUserRepository(client, db)
 	settingRepository := repository.NewSettingRepository(client)
 	settingService := service.NewSettingService(settingRepository, configConfig)
 	redisClient := infrastructure.ProvideRedis(configConfig)
@@ -57,12 +57,12 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	authHandler := handler.NewAuthHandler(configConfig, authService, userService)
 	userHandler := handler.NewUserHandler(userService)
 	apiKeyRepository := repository.NewApiKeyRepository(client)
-	groupRepository := repository.NewGroupRepository(client, sqlDB)
+	groupRepository := repository.NewGroupRepository(client, db)
 	userSubscriptionRepository := repository.NewUserSubscriptionRepository(client)
 	apiKeyCache := repository.NewApiKeyCache(redisClient)
 	apiKeyService := service.NewApiKeyService(apiKeyRepository, userRepository, groupRepository, userSubscriptionRepository, apiKeyCache, configConfig)
 	apiKeyHandler := handler.NewAPIKeyHandler(apiKeyService)
-	usageLogRepository := repository.NewUsageLogRepository(client, sqlDB)
+	usageLogRepository := repository.NewUsageLogRepository(client, db)
 	usageService := service.NewUsageService(usageLogRepository, userRepository)
 	usageHandler := handler.NewUsageHandler(usageService, apiKeyService)
 	redeemCodeRepository := repository.NewRedeemCodeRepository(client)
@@ -75,8 +75,8 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	subscriptionHandler := handler.NewSubscriptionHandler(subscriptionService)
 	dashboardService := service.NewDashboardService(usageLogRepository)
 	dashboardHandler := admin.NewDashboardHandler(dashboardService)
-	accountRepository := repository.NewAccountRepository(client, sqlDB)
-	proxyRepository := repository.NewProxyRepository(client, sqlDB)
+	accountRepository := repository.NewAccountRepository(client, db)
+	proxyRepository := repository.NewProxyRepository(client, db)
 	proxyExitInfoProber := repository.NewProxyExitInfoProber()
 	adminService := service.NewAdminService(userRepository, groupRepository, accountRepository, proxyRepository, apiKeyRepository, redeemCodeRepository, billingCacheService, proxyExitInfoProber)
 	adminUserHandler := admin.NewUserHandler(adminService)
@@ -95,7 +95,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	geminiTokenProvider := service.NewGeminiTokenProvider(accountRepository, geminiTokenCache, geminiOAuthService)
 	httpUpstream := repository.NewHTTPUpstream(configConfig)
 	accountTestService := service.NewAccountTestService(accountRepository, oAuthService, openAIOAuthService, geminiTokenProvider, httpUpstream)
-	concurrencyCache := repository.NewConcurrencyCache(redisClient)
+	concurrencyCache := repository.ProvideConcurrencyCache(redisClient, configConfig)
 	concurrencyService := service.NewConcurrencyService(concurrencyCache)
 	crsSyncService := service.NewCRSSyncService(accountRepository, proxyRepository, oAuthService, openAIOAuthService, geminiOAuthService)
 	accountHandler := admin.NewAccountHandler(adminService, oAuthService, openAIOAuthService, geminiOAuthService, rateLimitService, accountUsageService, accountTestService, concurrencyService, crsSyncService)
@@ -142,7 +142,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	httpServer := server.ProvideHTTPServer(configConfig, engine)
 	tokenRefreshService := service.ProvideTokenRefreshService(accountRepository, oAuthService, openAIOAuthService, geminiOAuthService, antigravityOAuthService, configConfig)
 	antigravityQuotaRefresher := service.ProvideAntigravityQuotaRefresher(accountRepository, proxyRepository, antigravityOAuthService, configConfig)
-	v := provideCleanup(client, redisClient, tokenRefreshService, pricingService, emailQueueService, oAuthService, openAIOAuthService, geminiOAuthService, antigravityOAuthService, antigravityQuotaRefresher)
+	v := provideCleanup(client, redisClient, tokenRefreshService, pricingService, emailQueueService, billingCacheService, oAuthService, openAIOAuthService, geminiOAuthService, antigravityOAuthService, antigravityQuotaRefresher)
 	application := &Application{
 		Server:  httpServer,
 		Cleanup: v,
@@ -170,6 +170,7 @@ func provideCleanup(
 	tokenRefresh *service.TokenRefreshService,
 	pricing *service.PricingService,
 	emailQueue *service.EmailQueueService,
+	billingCache *service.BillingCacheService,
 	oauth *service.OAuthService,
 	openaiOAuth *service.OpenAIOAuthService,
 	geminiOAuth *service.GeminiOAuthService,
@@ -196,6 +197,10 @@ func provideCleanup(
 				emailQueue.Stop()
 				return nil
 			}},
+			{"BillingCacheService", func() error {
+				billingCache.Stop()
+				return nil
+			}},
 			{"OAuthService", func() error {
 				oauth.Stop()
 				return nil
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -79,12 +79,29 @@ type GatewayConfig struct {
 	// 等待上游响应头的超时时间（秒），0表示无超时
 	// 注意：这不影响流式数据传输，只控制等待响应头的时间
 	ResponseHeaderTimeout int `mapstructure:"response_header_timeout"`
+	// 请求体最大字节数，用于网关请求体大小限制
+	MaxBodySize int64 `mapstructure:"max_body_size"`
+
+	// HTTP 上游连接池配置（性能优化：支持高并发场景调优）
+	// MaxIdleConns: 所有主机的最大空闲连接总数
+	MaxIdleConns int `mapstructure:"max_idle_conns"`
+	// MaxIdleConnsPerHost: 每个主机的最大空闲连接数（关键参数，影响连接复用率）
+	MaxIdleConnsPerHost int `mapstructure:"max_idle_conns_per_host"`
+	// MaxConnsPerHost: 每个主机的最大连接数（包括活跃+空闲），0表示无限制
+	MaxConnsPerHost int `mapstructure:"max_conns_per_host"`
+	// IdleConnTimeoutSeconds: 空闲连接超时时间（秒）
+	IdleConnTimeoutSeconds int `mapstructure:"idle_conn_timeout_seconds"`
+	// ConcurrencySlotTTLMinutes: 并发槽位过期时间（分钟）
+	// 应大于最长 LLM 请求时间，防止请求完成前槽位过期
+	ConcurrencySlotTTLMinutes int `mapstructure:"concurrency_slot_ttl_minutes"`
 }

 func (s *ServerConfig) Address() string {
 	return fmt.Sprintf("%s:%d", s.Host, s.Port)
 }

+// DatabaseConfig 数据库连接配置
+// 性能优化：新增连接池参数，避免频繁创建/销毁连接
 type DatabaseConfig struct {
 	Host     string `mapstructure:"host"`
 	Port     int    `mapstructure:"port"`
@@ -92,6 +109,15 @@ type DatabaseConfig struct {
 	Password string `mapstructure:"password"`
 	DBName   string `mapstructure:"dbname"`
 	SSLMode  string `mapstructure:"sslmode"`
+	// 连接池配置（性能优化：可配置化连接池参数）
+	// MaxOpenConns: 最大打开连接数，控制数据库连接上限，防止资源耗尽
+	MaxOpenConns int `mapstructure:"max_open_conns"`
+	// MaxIdleConns: 最大空闲连接数，保持热连接减少建连延迟
+	MaxIdleConns int `mapstructure:"max_idle_conns"`
+	// ConnMaxLifetimeMinutes: 连接最大存活时间，防止长连接导致的资源泄漏
+	ConnMaxLifetimeMinutes int `mapstructure:"conn_max_lifetime_minutes"`
+	// ConnMaxIdleTimeMinutes: 空闲连接最大存活时间，及时释放不活跃连接
+	ConnMaxIdleTimeMinutes int `mapstructure:"conn_max_idle_time_minutes"`
 }

 func (d *DatabaseConfig) DSN() string {
@@ -112,11 +138,24 @@ func (d *DatabaseConfig) DSNWithTimezone(tz string) string {
 	)
 }

+// RedisConfig Redis 连接配置
+// 性能优化：新增连接池和超时参数，提升高并发场景下的吞吐量
 type RedisConfig struct {
 	Host     string `mapstructure:"host"`
 	Port     int    `mapstructure:"port"`
 	Password string `mapstructure:"password"`
 	DB       int    `mapstructure:"db"`
+	// 连接池与超时配置（性能优化：可配置化连接池参数）
+	// DialTimeoutSeconds: 建立连接超时，防止慢连接阻塞
+	DialTimeoutSeconds int `mapstructure:"dial_timeout_seconds"`
+	// ReadTimeoutSeconds: 读取超时，避免慢查询阻塞连接池
+	ReadTimeoutSeconds int `mapstructure:"read_timeout_seconds"`
+	// WriteTimeoutSeconds: 写入超时，避免慢写入阻塞连接池
+	WriteTimeoutSeconds int `mapstructure:"write_timeout_seconds"`
+	// PoolSize: 连接池大小，控制最大并发连接数
+	PoolSize int `mapstructure:"pool_size"`
+	// MinIdleConns: 最小空闲连接数，保持热连接减少冷启动延迟
+	MinIdleConns int `mapstructure:"min_idle_conns"`
 }

 func (r *RedisConfig) Address() string {
@@ -203,12 +242,21 @@ func setDefaults() {
 	viper.SetDefault("database.password", "postgres")
 	viper.SetDefault("database.dbname", "sub2api")
 	viper.SetDefault("database.sslmode", "disable")
+	viper.SetDefault("database.max_open_conns", 50)
+	viper.SetDefault("database.max_idle_conns", 10)
+	viper.SetDefault("database.conn_max_lifetime_minutes", 30)
+	viper.SetDefault("database.conn_max_idle_time_minutes", 5)

 	// Redis
 	viper.SetDefault("redis.host", "localhost")
 	viper.SetDefault("redis.port", 6379)
 	viper.SetDefault("redis.password", "")
 	viper.SetDefault("redis.db", 0)
+	viper.SetDefault("redis.dial_timeout_seconds", 5)
+	viper.SetDefault("redis.read_timeout_seconds", 3)
+	viper.SetDefault("redis.write_timeout_seconds", 3)
+	viper.SetDefault("redis.pool_size", 128)
+	viper.SetDefault("redis.min_idle_conns", 10)

 	// JWT
 	viper.SetDefault("jwt.secret", "change-me-in-production")
@@ -240,6 +288,13 @@ func setDefaults() {

 	// Gateway
 	viper.SetDefault("gateway.response_header_timeout", 300) // 300秒(5分钟)等待上游响应头，LLM高负载时可能排队较久
+	viper.SetDefault("gateway.max_body_size", int64(100*1024*1024))
+	// HTTP 上游连接池配置（针对 5000+ 并发用户优化）
+	viper.SetDefault("gateway.max_idle_conns", 240)          // 最大空闲连接总数（HTTP/2 场景默认）
+	viper.SetDefault("gateway.max_idle_conns_per_host", 120) // 每主机最大空闲连接（HTTP/2 场景默认）
+	viper.SetDefault("gateway.max_conns_per_host", 240)      // 每主机最大连接数（含活跃，HTTP/2 场景默认）
+	viper.SetDefault("gateway.idle_conn_timeout_seconds", 300) // 空闲连接超时（秒）
+	viper.SetDefault("gateway.concurrency_slot_ttl_minutes", 15) // 并发槽位过期时间（支持超长请求）

 	// TokenRefresh
 	viper.SetDefault("token_refresh.enabled", true)
@@ -263,6 +318,57 @@ func (c *Config) Validate() error {
 	if c.JWT.Secret == "change-me-in-production" && c.Server.Mode == "release" {
 		return fmt.Errorf("jwt.secret must be changed in production")
 	}
+	if c.Database.MaxOpenConns <= 0 {
+		return fmt.Errorf("database.max_open_conns must be positive")
+	}
+	if c.Database.MaxIdleConns < 0 {
+		return fmt.Errorf("database.max_idle_conns must be non-negative")
+	}
+	if c.Database.MaxIdleConns > c.Database.MaxOpenConns {
+		return fmt.Errorf("database.max_idle_conns cannot exceed database.max_open_conns")
+	}
+	if c.Database.ConnMaxLifetimeMinutes < 0 {
+		return fmt.Errorf("database.conn_max_lifetime_minutes must be non-negative")
+	}
+	if c.Database.ConnMaxIdleTimeMinutes < 0 {
+		return fmt.Errorf("database.conn_max_idle_time_minutes must be non-negative")
+	}
+	if c.Redis.DialTimeoutSeconds <= 0 {
+		return fmt.Errorf("redis.dial_timeout_seconds must be positive")
+	}
+	if c.Redis.ReadTimeoutSeconds <= 0 {
+		return fmt.Errorf("redis.read_timeout_seconds must be positive")
+	}
+	if c.Redis.WriteTimeoutSeconds <= 0 {
+		return fmt.Errorf("redis.write_timeout_seconds must be positive")
+	}
+	if c.Redis.PoolSize <= 0 {
+		return fmt.Errorf("redis.pool_size must be positive")
+	}
+	if c.Redis.MinIdleConns < 0 {
+		return fmt.Errorf("redis.min_idle_conns must be non-negative")
+	}
+	if c.Redis.MinIdleConns > c.Redis.PoolSize {
+		return fmt.Errorf("redis.min_idle_conns cannot exceed redis.pool_size")
+	}
+	if c.Gateway.MaxBodySize <= 0 {
+		return fmt.Errorf("gateway.max_body_size must be positive")
+	}
+	if c.Gateway.MaxIdleConns <= 0 {
+		return fmt.Errorf("gateway.max_idle_conns must be positive")
+	}
+	if c.Gateway.MaxIdleConnsPerHost <= 0 {
+		return fmt.Errorf("gateway.max_idle_conns_per_host must be positive")
+	}
+	if c.Gateway.MaxConnsPerHost < 0 {
+		return fmt.Errorf("gateway.max_conns_per_host must be non-negative")
+	}
+	if c.Gateway.IdleConnTimeoutSeconds <= 0 {
+		return fmt.Errorf("gateway.idle_conn_timeout_seconds must be positive")
+	}
+	if c.Gateway.ConcurrencySlotTTLMinutes <= 0 {
+		return fmt.Errorf("gateway.concurrency_slot_ttl_minutes must be positive")
+	}
 	return nil
 }

--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -67,6 +67,10 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	// 读取请求体
 	body, err := io.ReadAll(c.Request.Body)
 	if err != nil {
+		if maxErr, ok := extractMaxBytesError(err); ok {
+			h.errorResponse(c, http.StatusRequestEntityTooLarge, "invalid_request_error", buildBodyTooLargeMessage(maxErr.Limit))
+			return
+		}
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to read request body")
 		return
 	}
@@ -76,15 +80,13 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 		return
 	}

-	// 解析请求获取模型名和stream
-	var req struct {
-		Model  string `json:"model"`
-		Stream bool   `json:"stream"`
-	}
-	if err := json.Unmarshal(body, &req); err != nil {
+	parsedReq, err := service.ParseGatewayRequest(body)
+	if err != nil {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
+	reqModel := parsedReq.Model
+	reqStream := parsedReq.Stream

 	// Track if we've started streaming (for error handling)
 	streamStarted := false
@@ -106,7 +108,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	defer h.concurrencyHelper.DecrementWaitCount(c.Request.Context(), subject.UserID)

 	// 1. 首先获取用户并发槽位
-	userReleaseFunc, err := h.concurrencyHelper.AcquireUserSlotWithWait(c, subject.UserID, subject.Concurrency, req.Stream, &streamStarted)
+	userReleaseFunc, err := h.concurrencyHelper.AcquireUserSlotWithWait(c, subject.UserID, subject.Concurrency, reqStream, &streamStarted)
 	if err != nil {
 		log.Printf("User concurrency acquire failed: %v", err)
 		h.handleConcurrencyError(c, err, "user", streamStarted)
@@ -124,7 +126,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	}

 	// 计算粘性会话hash
-	sessionHash := h.gatewayService.GenerateSessionHash(body)
+	sessionHash := h.gatewayService.GenerateSessionHash(parsedReq)

 	// 获取平台：优先使用强制平台（/antigravity 路由，中间件已设置 request.Context），否则使用分组平台
 	platform := ""
@@ -141,7 +143,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 		lastFailoverStatus := 0

 		for {
-			account, err := h.geminiCompatService.SelectAccountForModelWithExclusions(c.Request.Context(), apiKey.GroupID, sessionHash, req.Model, failedAccountIDs)
+			account, err := h.geminiCompatService.SelectAccountForModelWithExclusions(c.Request.Context(), apiKey.GroupID, sessionHash, reqModel, failedAccountIDs)
 			if err != nil {
 				if len(failedAccountIDs) == 0 {
 					h.handleStreamingAwareError(c, http.StatusServiceUnavailable, "api_error", "No available accounts: "+err.Error(), streamStarted)
@@ -153,16 +155,16 @@ func (h *GatewayHandler) Messages(c *gin.Context) {

 			// 检查预热请求拦截（在账号选择后、转发前检查）
 			if account.IsInterceptWarmupEnabled() && isWarmupRequest(body) {
-				if req.Stream {
-					sendMockWarmupStream(c, req.Model)
+				if reqStream {
+					sendMockWarmupStream(c, reqModel)
 				} else {
-					sendMockWarmupResponse(c, req.Model)
+					sendMockWarmupResponse(c, reqModel)
 				}
 				return
 			}

 			// 3. 获取账号并发槽位
-			accountReleaseFunc, err := h.concurrencyHelper.AcquireAccountSlotWithWait(c, account.ID, account.Concurrency, req.Stream, &streamStarted)
+			accountReleaseFunc, err := h.concurrencyHelper.AcquireAccountSlotWithWait(c, account.ID, account.Concurrency, reqStream, &streamStarted)
 			if err != nil {
 				log.Printf("Account concurrency acquire failed: %v", err)
 				h.handleConcurrencyError(c, err, "account", streamStarted)
@@ -172,7 +174,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 			// 转发请求 - 根据账号平台分流
 			var result *service.ForwardResult
 			if account.Platform == service.PlatformAntigravity {
-				result, err = h.antigravityGatewayService.ForwardGemini(c.Request.Context(), c, account, req.Model, "generateContent", req.Stream, body)
+				result, err = h.antigravityGatewayService.ForwardGemini(c.Request.Context(), c, account, reqModel, "generateContent", reqStream, body)
 			} else {
 				result, err = h.geminiCompatService.Forward(c.Request.Context(), c, account, body)
 			}
@@ -223,7 +225,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {

 	for {
 		// 选择支持该模型的账号
-		account, err := h.gatewayService.SelectAccountForModelWithExclusions(c.Request.Context(), apiKey.GroupID, sessionHash, req.Model, failedAccountIDs)
+		account, err := h.gatewayService.SelectAccountForModelWithExclusions(c.Request.Context(), apiKey.GroupID, sessionHash, reqModel, failedAccountIDs)
 		if err != nil {
 			if len(failedAccountIDs) == 0 {
 				h.handleStreamingAwareError(c, http.StatusServiceUnavailable, "api_error", "No available accounts: "+err.Error(), streamStarted)
@@ -235,16 +237,16 @@ func (h *GatewayHandler) Messages(c *gin.Context) {

 		// 检查预热请求拦截（在账号选择后、转发前检查）
 		if account.IsInterceptWarmupEnabled() && isWarmupRequest(body) {
-			if req.Stream {
-				sendMockWarmupStream(c, req.Model)
+			if reqStream {
+				sendMockWarmupStream(c, reqModel)
 			} else {
-				sendMockWarmupResponse(c, req.Model)
+				sendMockWarmupResponse(c, reqModel)
 			}
 			return
 		}

 		// 3. 获取账号并发槽位
-		accountReleaseFunc, err := h.concurrencyHelper.AcquireAccountSlotWithWait(c, account.ID, account.Concurrency, req.Stream, &streamStarted)
+		accountReleaseFunc, err := h.concurrencyHelper.AcquireAccountSlotWithWait(c, account.ID, account.Concurrency, reqStream, &streamStarted)
 		if err != nil {
 			log.Printf("Account concurrency acquire failed: %v", err)
 			h.handleConcurrencyError(c, err, "account", streamStarted)
@@ -256,7 +258,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 		if account.Platform == service.PlatformAntigravity {
 			result, err = h.antigravityGatewayService.Forward(c.Request.Context(), c, account, body)
 		} else {
-			result, err = h.gatewayService.Forward(c.Request.Context(), c, account, body)
+			result, err = h.gatewayService.Forward(c.Request.Context(), c, account, parsedReq)
 		}
 		if accountReleaseFunc != nil {
 			accountReleaseFunc()
@@ -496,6 +498,10 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 	// 读取请求体
 	body, err := io.ReadAll(c.Request.Body)
 	if err != nil {
+		if maxErr, ok := extractMaxBytesError(err); ok {
+			h.errorResponse(c, http.StatusRequestEntityTooLarge, "invalid_request_error", buildBodyTooLargeMessage(maxErr.Limit))
+			return
+		}
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to read request body")
 		return
 	}
@@ -505,11 +511,8 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 		return
 	}

-	// 解析请求获取模型名
-	var req struct {
-		Model string `json:"model"`
-	}
-	if err := json.Unmarshal(body, &req); err != nil {
+	parsedReq, err := service.ParseGatewayRequest(body)
+	if err != nil {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
@@ -525,17 +528,17 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 	}

 	// 计算粘性会话 hash
-	sessionHash := h.gatewayService.GenerateSessionHash(body)
+	sessionHash := h.gatewayService.GenerateSessionHash(parsedReq)

 	// 选择支持该模型的账号
-	account, err := h.gatewayService.SelectAccountForModel(c.Request.Context(), apiKey.GroupID, sessionHash, req.Model)
+	account, err := h.gatewayService.SelectAccountForModel(c.Request.Context(), apiKey.GroupID, sessionHash, parsedReq.Model)
 	if err != nil {
 		h.errorResponse(c, http.StatusServiceUnavailable, "api_error", "No available accounts: "+err.Error())
 		return
 	}

 	// 转发请求（不记录使用量）
-	if err := h.gatewayService.ForwardCountTokens(c.Request.Context(), c, account, body); err != nil {
+	if err := h.gatewayService.ForwardCountTokens(c.Request.Context(), c, account, parsedReq); err != nil {
 		log.Printf("Forward count_tokens request failed: %v", err)
 		// 错误响应已在 ForwardCountTokens 中处理
 		return
--- a/backend/internal/handler/gateway_helper.go
+++ b/backend/internal/handler/gateway_helper.go
@@ -3,6 +3,7 @@ package handler
 import (
 	"context"
 	"fmt"
+	"math/rand"
 	"net/http"
 	"time"

@@ -11,11 +12,28 @@ import (
 	"github.com/gin-gonic/gin"
 )

+// 并发槽位等待相关常量
+//
+// 性能优化说明：
+// 原实现使用固定间隔（100ms）轮询并发槽位，存在以下问题：
+// 1. 高并发时频繁轮询增加 Redis 压力
+// 2. 固定间隔可能导致多个请求同时重试（惊群效应）
+//
+// 新实现使用指数退避 + 抖动算法：
+// 1. 初始退避 100ms，每次乘以 1.5，最大 2s
+// 2. 添加 ±20% 的随机抖动，分散重试时间点
+// 3. 减少 Redis 压力，避免惊群效应
 const (
-	// maxConcurrencyWait is the maximum time to wait for a concurrency slot
+	// maxConcurrencyWait 等待并发槽位的最大时间
 	maxConcurrencyWait = 30 * time.Second
-	// pingInterval is the interval for sending ping events during slot wait
+	// pingInterval 流式响应等待时发送 ping 的间隔
 	pingInterval = 15 * time.Second
+	// initialBackoff 初始退避时间
+	initialBackoff = 100 * time.Millisecond
+	// backoffMultiplier 退避时间乘数（指数退避）
+	backoffMultiplier = 1.5
+	// maxBackoff 最大退避时间
+	maxBackoff = 2 * time.Second
 )

 // SSEPingFormat defines the format of SSE ping events for different platforms
@@ -131,8 +149,10 @@ func (h *ConcurrencyHelper) waitForSlotWithPing(c *gin.Context, slotType string,
 		pingCh = pingTicker.C
 	}

-	pollTicker := time.NewTicker(100 * time.Millisecond)
-	defer pollTicker.Stop()
+	backoff := initialBackoff
+	timer := time.NewTimer(backoff)
+	defer timer.Stop()
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))

 	for {
 		select {
@@ -156,7 +176,7 @@ func (h *ConcurrencyHelper) waitForSlotWithPing(c *gin.Context, slotType string,
 			}
 			flusher.Flush()

-		case <-pollTicker.C:
+		case <-timer.C:
 			// Try to acquire slot
 			var result *service.AcquireResult
 			var err error
@@ -174,6 +194,35 @@ func (h *ConcurrencyHelper) waitForSlotWithPing(c *gin.Context, slotType string,
 			if result.Acquired {
 				return result.ReleaseFunc, nil
 			}
+			backoff = nextBackoff(backoff, rng)
+			timer.Reset(backoff)
 		}
 	}
 }
+
+// nextBackoff 计算下一次退避时间
+// 性能优化：使用指数退避 + 随机抖动，避免惊群效应
+// current: 当前退避时间
+// rng: 随机数生成器（可为 nil，此时不添加抖动）
+// 返回值：下一次退避时间（100ms ~ 2s 之间）
+func nextBackoff(current time.Duration, rng *rand.Rand) time.Duration {
+	// 指数退避：当前时间 * 1.5
+	next := time.Duration(float64(current) * backoffMultiplier)
+	if next > maxBackoff {
+		next = maxBackoff
+	}
+	if rng == nil {
+		return next
+	}
+	// 添加 ±20% 的随机抖动（jitter 范围 0.8 ~ 1.2）
+	// 抖动可以分散多个请求的重试时间点，避免同时冲击 Redis
+	jitter := 0.8 + rng.Float64()*0.4
+	jittered := time.Duration(float64(next) * jitter)
+	if jittered < initialBackoff {
+		return initialBackoff
+	}
+	if jittered > maxBackoff {
+		return maxBackoff
+	}
+	return jittered
+}
--- a/backend/internal/handler/gemini_v1beta_handler.go
+++ b/backend/internal/handler/gemini_v1beta_handler.go
@@ -148,6 +148,10 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {

 	body, err := io.ReadAll(c.Request.Body)
 	if err != nil {
+		if maxErr, ok := extractMaxBytesError(err); ok {
+			googleError(c, http.StatusRequestEntityTooLarge, buildBodyTooLargeMessage(maxErr.Limit))
+			return
+		}
 		googleError(c, http.StatusBadRequest, "Failed to read request body")
 		return
 	}
@@ -191,7 +195,8 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 	}

 	// 3) select account (sticky session based on request body)
-	sessionHash := h.gatewayService.GenerateSessionHash(body)
+	parsedReq, _ := service.ParseGatewayRequest(body)
+	sessionHash := h.gatewayService.GenerateSessionHash(parsedReq)
 	const maxAccountSwitches = 3
 	switchCount := 0
 	failedAccountIDs := make(map[int64]struct{})
--- a/backend/internal/handler/openai_gateway_handler.go
+++ b/backend/internal/handler/openai_gateway_handler.go
@@ -56,6 +56,10 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 	// Read request body
 	body, err := io.ReadAll(c.Request.Body)
 	if err != nil {
+		if maxErr, ok := extractMaxBytesError(err); ok {
+			h.errorResponse(c, http.StatusRequestEntityTooLarge, "invalid_request_error", buildBodyTooLargeMessage(maxErr.Limit))
+			return
+		}
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to read request body")
 		return
 	}
--- a/backend/internal/handler/request_body_limit.go
+++ b/backend/internal/handler/request_body_limit.go
@@ -0,0 +1,27 @@
+package handler
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+func extractMaxBytesError(err error) (*http.MaxBytesError, bool) {
+	var maxErr *http.MaxBytesError
+	if errors.As(err, &maxErr) {
+		return maxErr, true
+	}
+	return nil, false
+}
+
+func formatBodyLimit(limit int64) string {
+	const mb = 1024 * 1024
+	if limit >= mb {
+		return fmt.Sprintf("%dMB", limit/mb)
+	}
+	return fmt.Sprintf("%dB", limit)
+}
+
+func buildBodyTooLargeMessage(limit int64) string {
+	return fmt.Sprintf("Request body too large, limit is %s", formatBodyLimit(limit))
+}
--- a/backend/internal/handler/request_body_limit_test.go
+++ b/backend/internal/handler/request_body_limit_test.go
@@ -0,0 +1,45 @@
+package handler
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRequestBodyLimitTooLarge(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	limit := int64(16)
+	router := gin.New()
+	router.Use(middleware.RequestBodyLimit(limit))
+	router.POST("/test", func(c *gin.Context) {
+		_, err := io.ReadAll(c.Request.Body)
+		if err != nil {
+			if maxErr, ok := extractMaxBytesError(err); ok {
+				c.JSON(http.StatusRequestEntityTooLarge, gin.H{
+					"error": buildBodyTooLargeMessage(maxErr.Limit),
+				})
+				return
+			}
+			c.JSON(http.StatusBadRequest, gin.H{
+				"error": "read_failed",
+			})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{"ok": true})
+	})
+
+	payload := bytes.Repeat([]byte("a"), int(limit+1))
+	req := httptest.NewRequest(http.MethodPost, "/test", bytes.NewReader(payload))
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, req)
+
+	require.Equal(t, http.StatusRequestEntityTooLarge, recorder.Code)
+	require.Contains(t, recorder.Body.String(), buildBodyTooLargeMessage(limit))
+}
--- a/backend/internal/infrastructure/db_pool.go
+++ b/backend/internal/infrastructure/db_pool.go
@@ -0,0 +1,32 @@
+package infrastructure
+
+import (
+	"database/sql"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+)
+
+type dbPoolSettings struct {
+	MaxOpenConns    int
+	MaxIdleConns    int
+	ConnMaxLifetime time.Duration
+	ConnMaxIdleTime time.Duration
+}
+
+func buildDBPoolSettings(cfg *config.Config) dbPoolSettings {
+	return dbPoolSettings{
+		MaxOpenConns:    cfg.Database.MaxOpenConns,
+		MaxIdleConns:    cfg.Database.MaxIdleConns,
+		ConnMaxLifetime: time.Duration(cfg.Database.ConnMaxLifetimeMinutes) * time.Minute,
+		ConnMaxIdleTime: time.Duration(cfg.Database.ConnMaxIdleTimeMinutes) * time.Minute,
+	}
+}
+
+func applyDBPoolSettings(db *sql.DB, cfg *config.Config) {
+	settings := buildDBPoolSettings(cfg)
+	db.SetMaxOpenConns(settings.MaxOpenConns)
+	db.SetMaxIdleConns(settings.MaxIdleConns)
+	db.SetConnMaxLifetime(settings.ConnMaxLifetime)
+	db.SetConnMaxIdleTime(settings.ConnMaxIdleTime)
+}
--- a/backend/internal/infrastructure/db_pool_test.go
+++ b/backend/internal/infrastructure/db_pool_test.go
@@ -0,0 +1,50 @@
+package infrastructure
+
+import (
+	"database/sql"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+
+	_ "github.com/lib/pq"
+)
+
+func TestBuildDBPoolSettings(t *testing.T) {
+	cfg := &config.Config{
+		Database: config.DatabaseConfig{
+			MaxOpenConns:           50,
+			MaxIdleConns:           10,
+			ConnMaxLifetimeMinutes: 30,
+			ConnMaxIdleTimeMinutes: 5,
+		},
+	}
+
+	settings := buildDBPoolSettings(cfg)
+	require.Equal(t, 50, settings.MaxOpenConns)
+	require.Equal(t, 10, settings.MaxIdleConns)
+	require.Equal(t, 30*time.Minute, settings.ConnMaxLifetime)
+	require.Equal(t, 5*time.Minute, settings.ConnMaxIdleTime)
+}
+
+func TestApplyDBPoolSettings(t *testing.T) {
+	cfg := &config.Config{
+		Database: config.DatabaseConfig{
+			MaxOpenConns:           40,
+			MaxIdleConns:           8,
+			ConnMaxLifetimeMinutes: 15,
+			ConnMaxIdleTimeMinutes: 3,
+		},
+	}
+
+	db, err := sql.Open("postgres", "host=127.0.0.1 port=5432 user=postgres sslmode=disable")
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = db.Close()
+	})
+
+	applyDBPoolSettings(db, cfg)
+	stats := db.Stats()
+	require.Equal(t, 40, stats.MaxOpenConnections)
+}
--- a/backend/internal/infrastructure/ent.go
+++ b/backend/internal/infrastructure/ent.go
@@ -51,6 +51,7 @@ func InitEnt(cfg *config.Config) (*ent.Client, *sql.DB, error) {
 	if err != nil {
 		return nil, nil, err
 	}
+	applyDBPoolSettings(drv.DB(), cfg)

 	// 确保数据库 schema 已准备就绪。
 	// SQL 迁移文件是 schema 的权威来源（source of truth）。
--- a/backend/internal/infrastructure/redis.go
+++ b/backend/internal/infrastructure/redis.go
@@ -1,16 +1,39 @@
 package infrastructure

 import (
+	"time"
+
 	"github.com/Wei-Shaw/sub2api/internal/config"

 	"github.com/redis/go-redis/v9"
 )

 // InitRedis 初始化 Redis 客户端
+//
+// 性能优化说明：
+// 原实现使用 go-redis 默认配置，未设置连接池和超时参数：
+// 1. 默认连接池大小可能不足以支撑高并发
+// 2. 无超时控制可能导致慢操作阻塞
+//
+// 新实现支持可配置的连接池和超时参数：
+// 1. PoolSize: 控制最大并发连接数（默认 128）
+// 2. MinIdleConns: 保持最小空闲连接，减少冷启动延迟（默认 10）
+// 3. DialTimeout/ReadTimeout/WriteTimeout: 精确控制各阶段超时
 func InitRedis(cfg *config.Config) *redis.Client {
-	return redis.NewClient(&redis.Options{
-		Addr:     cfg.Redis.Address(),
-		Password: cfg.Redis.Password,
-		DB:       cfg.Redis.DB,
-	})
+	return redis.NewClient(buildRedisOptions(cfg))
+}
+
+// buildRedisOptions 构建 Redis 连接选项
+// 从配置文件读取连接池和超时参数，支持生产环境调优
+func buildRedisOptions(cfg *config.Config) *redis.Options {
+	return &redis.Options{
+		Addr:         cfg.Redis.Address(),
+		Password:     cfg.Redis.Password,
+		DB:           cfg.Redis.DB,
+		DialTimeout:  time.Duration(cfg.Redis.DialTimeoutSeconds) * time.Second,  // 建连超时
+		ReadTimeout:  time.Duration(cfg.Redis.ReadTimeoutSeconds) * time.Second,  // 读取超时
+		WriteTimeout: time.Duration(cfg.Redis.WriteTimeoutSeconds) * time.Second, // 写入超时
+		PoolSize:     cfg.Redis.PoolSize,                                          // 连接池大小
+		MinIdleConns: cfg.Redis.MinIdleConns,                                      // 最小空闲连接
+	}
 }
--- a/backend/internal/infrastructure/redis_test.go
+++ b/backend/internal/infrastructure/redis_test.go
@@ -0,0 +1,35 @@
+package infrastructure
+
+import (
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBuildRedisOptions(t *testing.T) {
+	cfg := &config.Config{
+		Redis: config.RedisConfig{
+			Host:                "localhost",
+			Port:                6379,
+			Password:            "secret",
+			DB:                  2,
+			DialTimeoutSeconds:  5,
+			ReadTimeoutSeconds:  3,
+			WriteTimeoutSeconds: 4,
+			PoolSize:            100,
+			MinIdleConns:        10,
+		},
+	}
+
+	opts := buildRedisOptions(cfg)
+	require.Equal(t, "localhost:6379", opts.Addr)
+	require.Equal(t, "secret", opts.Password)
+	require.Equal(t, 2, opts.DB)
+	require.Equal(t, 5*time.Second, opts.DialTimeout)
+	require.Equal(t, 3*time.Second, opts.ReadTimeout)
+	require.Equal(t, 4*time.Second, opts.WriteTimeout)
+	require.Equal(t, 100, opts.PoolSize)
+	require.Equal(t, 10, opts.MinIdleConns)
+}
--- a/backend/internal/pkg/httpclient/pool.go
+++ b/backend/internal/pkg/httpclient/pool.go
@@ -0,0 +1,152 @@
+// Package httpclient 提供共享 HTTP 客户端池
+//
+// 性能优化说明：
+// 原实现在多个服务中重复创建 http.Client：
+// 1. proxy_probe_service.go: 每次探测创建新客户端
+// 2. pricing_service.go: 每次请求创建新客户端
+// 3. turnstile_service.go: 每次验证创建新客户端
+// 4. github_release_service.go: 每次请求创建新客户端
+// 5. claude_usage_service.go: 每次请求创建新客户端
+//
+// 新实现使用统一的客户端池：
+// 1. 相同配置复用同一 http.Client 实例
+// 2. 复用 Transport 连接池，减少 TCP/TLS 握手开销
+// 3. 支持 HTTP/HTTPS/SOCKS5 代理
+// 4. 支持严格代理模式（代理失败则返回错误）
+package httpclient
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/proxy"
+)
+
+// Transport 连接池默认配置
+const (
+	defaultMaxIdleConns        = 100              // 最大空闲连接数
+	defaultMaxIdleConnsPerHost = 10               // 每个主机最大空闲连接数
+	defaultIdleConnTimeout     = 90 * time.Second // 空闲连接超时时间
+)
+
+// Options 定义共享 HTTP 客户端的构建参数
+type Options struct {
+	ProxyURL              string        // 代理 URL（支持 http/https/socks5）
+	Timeout               time.Duration // 请求总超时时间
+	ResponseHeaderTimeout time.Duration // 等待响应头超时时间
+	InsecureSkipVerify    bool          // 是否跳过 TLS 证书验证
+	ProxyStrict           bool          // 严格代理模式：代理失败时返回错误而非回退
+
+	// 可选的连接池参数（不设置则使用默认值）
+	MaxIdleConns        int // 最大空闲连接总数（默认 100）
+	MaxIdleConnsPerHost int // 每主机最大空闲连接（默认 10）
+	MaxConnsPerHost     int // 每主机最大连接数（默认 0 无限制）
+}
+
+// sharedClients 存储按配置参数缓存的 http.Client 实例
+var sharedClients sync.Map
+
+// GetClient 返回共享的 HTTP 客户端实例
+// 性能优化：相同配置复用同一客户端，避免重复创建 Transport
+func GetClient(opts Options) (*http.Client, error) {
+	key := buildClientKey(opts)
+	if cached, ok := sharedClients.Load(key); ok {
+		return cached.(*http.Client), nil
+	}
+
+	client, err := buildClient(opts)
+	if err != nil {
+		if opts.ProxyStrict {
+			return nil, err
+		}
+		fallback := opts
+		fallback.ProxyURL = ""
+		client, _ = buildClient(fallback)
+	}
+
+	actual, _ := sharedClients.LoadOrStore(key, client)
+	return actual.(*http.Client), nil
+}
+
+func buildClient(opts Options) (*http.Client, error) {
+	transport, err := buildTransport(opts)
+	if err != nil {
+		return nil, err
+	}
+
+	return &http.Client{
+		Transport: transport,
+		Timeout:   opts.Timeout,
+	}, nil
+}
+
+func buildTransport(opts Options) (*http.Transport, error) {
+	// 使用自定义值或默认值
+	maxIdleConns := opts.MaxIdleConns
+	if maxIdleConns <= 0 {
+		maxIdleConns = defaultMaxIdleConns
+	}
+	maxIdleConnsPerHost := opts.MaxIdleConnsPerHost
+	if maxIdleConnsPerHost <= 0 {
+		maxIdleConnsPerHost = defaultMaxIdleConnsPerHost
+	}
+
+	transport := &http.Transport{
+		MaxIdleConns:          maxIdleConns,
+		MaxIdleConnsPerHost:   maxIdleConnsPerHost,
+		MaxConnsPerHost:       opts.MaxConnsPerHost, // 0 表示无限制
+		IdleConnTimeout:       defaultIdleConnTimeout,
+		ResponseHeaderTimeout: opts.ResponseHeaderTimeout,
+	}
+
+	if opts.InsecureSkipVerify {
+		transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+	}
+
+	proxyURL := strings.TrimSpace(opts.ProxyURL)
+	if proxyURL == "" {
+		return transport, nil
+	}
+
+	parsed, err := url.Parse(proxyURL)
+	if err != nil {
+		return nil, err
+	}
+
+	switch strings.ToLower(parsed.Scheme) {
+	case "http", "https":
+		transport.Proxy = http.ProxyURL(parsed)
+	case "socks5", "socks5h":
+		dialer, err := proxy.FromURL(parsed, proxy.Direct)
+		if err != nil {
+			return nil, err
+		}
+		transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+			return dialer.Dial(network, addr)
+		}
+	default:
+		return nil, fmt.Errorf("unsupported proxy protocol: %s", parsed.Scheme)
+	}
+
+	return transport, nil
+}
+
+func buildClientKey(opts Options) string {
+	return fmt.Sprintf("%s|%s|%s|%t|%t|%d|%d|%d",
+		strings.TrimSpace(opts.ProxyURL),
+		opts.Timeout.String(),
+		opts.ResponseHeaderTimeout.String(),
+		opts.InsecureSkipVerify,
+		opts.ProxyStrict,
+		opts.MaxIdleConns,
+		opts.MaxIdleConnsPerHost,
+		opts.MaxConnsPerHost,
+	)
+}
--- a/backend/internal/repository/claude_oauth_service.go
+++ b/backend/internal/repository/claude_oauth_service.go
@@ -233,15 +233,11 @@ func (s *claudeOAuthService) RefreshToken(ctx context.Context, refreshToken, pro
 }

 func createReqClient(proxyURL string) *req.Client {
-	client := req.C().
-		ImpersonateChrome().
-		SetTimeout(60 * time.Second)
-
-	if proxyURL != "" {
-		client.SetProxyURL(proxyURL)
-	}
-
-	return client
+	return getSharedReqClient(reqClientOptions{
+		ProxyURL:    proxyURL,
+		Timeout:     60 * time.Second,
+		Impersonate: true,
+	})
 }

 func prefix(s string, n int) string {
--- a/backend/internal/repository/claude_usage_service.go
+++ b/backend/internal/repository/claude_usage_service.go
@@ -6,9 +6,9 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

@@ -23,20 +23,12 @@ func NewClaudeUsageFetcher() service.ClaudeUsageFetcher {
 }

 func (s *claudeUsageService) FetchUsage(ctx context.Context, accessToken, proxyURL string) (*service.ClaudeUsageResponse, error) {
-	transport, ok := http.DefaultTransport.(*http.Transport)
-	if !ok {
-		return nil, fmt.Errorf("failed to get default transport")
-	}
-	transport = transport.Clone()
-	if proxyURL != "" {
-		if parsedURL, err := url.Parse(proxyURL); err == nil {
-			transport.Proxy = http.ProxyURL(parsedURL)
-		}
-	}
-
-	client := &http.Client{
-		Transport: transport,
-		Timeout:   30 * time.Second,
+	client, err := httpclient.GetClient(httpclient.Options{
+		ProxyURL: proxyURL,
+		Timeout:  30 * time.Second,
+	})
+	if err != nil {
+		client = &http.Client{Timeout: 30 * time.Second}
 	}

 	req, err := http.NewRequestWithContext(ctx, "GET", s.usageURL, nil)
--- a/backend/internal/repository/concurrency_cache.go
+++ b/backend/internal/repository/concurrency_cache.go
@@ -3,67 +3,90 @@ package repository
 import (
 	"context"
 	"fmt"
-	"time"

 	"github.com/Wei-Shaw/sub2api/internal/service"
 	"github.com/redis/go-redis/v9"
 )

+// 并发控制缓存常量定义
+//
+// 性能优化说明：
+// 原实现使用 SCAN 命令遍历独立的槽位键（concurrency:account:{id}:{requestID}），
+// 在高并发场景下 SCAN 需要多次往返，且遍历大量键时性能下降明显。
+//
+// 新实现改用 Redis 有序集合（Sorted Set）：
+// 1. 每个账号/用户只有一个键，成员为 requestID，分数为时间戳
+// 2. 使用 ZCARD 原子获取并发数，时间复杂度 O(1)
+// 3. 使用 ZREMRANGEBYSCORE 清理过期槽位，避免手动管理 TTL
+// 4. 单次 Redis 调用完成计数，减少网络往返
 const (
-	// Key prefixes for independent slot keys
-	// Format: concurrency:account:{accountID}:{requestID}
+	// 并发槽位键前缀（有序集合）
+	// 格式: concurrency:account:{accountID}
 	accountSlotKeyPrefix = "concurrency:account:"
-	// Format: concurrency:user:{userID}:{requestID}
+	// 格式: concurrency:user:{userID}
 	userSlotKeyPrefix = "concurrency:user:"
-	// Wait queue keeps counter format: concurrency:wait:{userID}
+	// 等待队列计数器格式: concurrency:wait:{userID}
 	waitQueueKeyPrefix = "concurrency:wait:"

-	// Slot TTL - each slot expires independently
-	slotTTL = 5 * time.Minute
+	// 默认槽位过期时间（分钟），可通过配置覆盖
+	defaultSlotTTLMinutes = 15
 )

 var (
-	// acquireScript uses SCAN to count existing slots and creates new slot if under limit
-	// KEYS[1] = pattern for SCAN (e.g., "concurrency:account:2:*")
-	// KEYS[2] = full slot key (e.g., "concurrency:account:2:req_xxx")
+	// acquireScript 使用有序集合计数并在未达上限时添加槽位
+	// 使用 Redis TIME 命令获取服务器时间，避免多实例时钟不同步问题
+	// KEYS[1] = 有序集合键 (concurrency:account:{id} / concurrency:user:{id})
 	// ARGV[1] = maxConcurrency
-	// ARGV[2] = TTL in seconds
+	// ARGV[2] = TTL（秒）
+	// ARGV[3] = requestID
 	acquireScript = redis.NewScript(`
-		local pattern = KEYS[1]
-		local slotKey = KEYS[2]
+		local key = KEYS[1]
 		local maxConcurrency = tonumber(ARGV[1])
 		local ttl = tonumber(ARGV[2])
+		local requestID = ARGV[3]

-		-- Count existing slots using SCAN
-		local cursor = "0"
-		local count = 0
-		repeat
-			local result = redis.call('SCAN', cursor, 'MATCH', pattern, 'COUNT', 100)
-			cursor = result[1]
-			count = count + #result[2]
-		until cursor == "0"
+		-- 使用 Redis 服务器时间，确保多实例时钟一致
+		local timeResult = redis.call('TIME')
+		local now = tonumber(timeResult[1])
+		local expireBefore = now - ttl

-		-- Check if we can acquire a slot
+		-- 清理过期槽位
+		redis.call('ZREMRANGEBYSCORE', key, '-inf', expireBefore)
+
+		-- 检查是否已存在（支持重试场景刷新时间戳）
+		local exists = redis.call('ZSCORE', key, requestID)
+		if exists ~= false then
+			redis.call('ZADD', key, now, requestID)
+			redis.call('EXPIRE', key, ttl)
+			return 1
+		end
+
+		-- 检查是否达到并发上限
+		local count = redis.call('ZCARD', key)
 		if count < maxConcurrency then
-			redis.call('SET', slotKey, '1', 'EX', ttl)
+			redis.call('ZADD', key, now, requestID)
+			redis.call('EXPIRE', key, ttl)
 			return 1
 		end

 		return 0
 	`)

-	// getCountScript counts slots using SCAN
-	// KEYS[1] = pattern for SCAN
+	// getCountScript 统计有序集合中的槽位数量并清理过期条目
+	// 使用 Redis TIME 命令获取服务器时间
+	// KEYS[1] = 有序集合键
+	// ARGV[1] = TTL（秒）
 	getCountScript = redis.NewScript(`
-		local pattern = KEYS[1]
-		local cursor = "0"
-		local count = 0
-		repeat
-			local result = redis.call('SCAN', cursor, 'MATCH', pattern, 'COUNT', 100)
-			cursor = result[1]
-			count = count + #result[2]
-		until cursor == "0"
-		return count
+		local key = KEYS[1]
+		local ttl = tonumber(ARGV[1])
+
+		-- 使用 Redis 服务器时间
+		local timeResult = redis.call('TIME')
+		local now = tonumber(timeResult[1])
+		local expireBefore = now - ttl
+
+		redis.call('ZREMRANGEBYSCORE', key, '-inf', expireBefore)
+		return redis.call('ZCARD', key)
 	`)

 	// incrementWaitScript - only sets TTL on first creation to avoid refreshing
@@ -103,28 +126,29 @@ var (
 )

 type concurrencyCache struct {
-	rdb *redis.Client
+	rdb           *redis.Client
+	slotTTLSeconds int // 槽位过期时间（秒）
 }

-func NewConcurrencyCache(rdb *redis.Client) service.ConcurrencyCache {
-	return &concurrencyCache{rdb: rdb}
+// NewConcurrencyCache 创建并发控制缓存
+// slotTTLMinutes: 槽位过期时间（分钟），0 或负数使用默认值 15 分钟
+func NewConcurrencyCache(rdb *redis.Client, slotTTLMinutes int) service.ConcurrencyCache {
+	if slotTTLMinutes <= 0 {
+		slotTTLMinutes = defaultSlotTTLMinutes
+	}
+	return &concurrencyCache{
+		rdb:           rdb,
+		slotTTLSeconds: slotTTLMinutes * 60,
+	}
 }

 // Helper functions for key generation
-func accountSlotKey(accountID int64, requestID string) string {
-	return fmt.Sprintf("%s%d:%s", accountSlotKeyPrefix, accountID, requestID)
+func accountSlotKey(accountID int64) string {
+	return fmt.Sprintf("%s%d", accountSlotKeyPrefix, accountID)
 }

-func accountSlotPattern(accountID int64) string {
-	return fmt.Sprintf("%s%d:*", accountSlotKeyPrefix, accountID)
-}
-
-func userSlotKey(userID int64, requestID string) string {
-	return fmt.Sprintf("%s%d:%s", userSlotKeyPrefix, userID, requestID)
-}
-
-func userSlotPattern(userID int64) string {
-	return fmt.Sprintf("%s%d:*", userSlotKeyPrefix, userID)
+func userSlotKey(userID int64) string {
+	return fmt.Sprintf("%s%d", userSlotKeyPrefix, userID)
 }

 func waitQueueKey(userID int64) string {
@@ -134,10 +158,9 @@ func waitQueueKey(userID int64) string {
 // Account slot operations

 func (c *concurrencyCache) AcquireAccountSlot(ctx context.Context, accountID int64, maxConcurrency int, requestID string) (bool, error) {
-	pattern := accountSlotPattern(accountID)
-	slotKey := accountSlotKey(accountID, requestID)
-
-	result, err := acquireScript.Run(ctx, c.rdb, []string{pattern, slotKey}, maxConcurrency, int(slotTTL.Seconds())).Int()
+	key := accountSlotKey(accountID)
+	// 时间戳在 Lua 脚本内使用 Redis TIME 命令获取，确保多实例时钟一致
+	result, err := acquireScript.Run(ctx, c.rdb, []string{key}, maxConcurrency, c.slotTTLSeconds, requestID).Int()
 	if err != nil {
 		return false, err
 	}
@@ -145,13 +168,14 @@ func (c *concurrencyCache) AcquireAccountSlot(ctx context.Context, accountID int
 }

 func (c *concurrencyCache) ReleaseAccountSlot(ctx context.Context, accountID int64, requestID string) error {
-	slotKey := accountSlotKey(accountID, requestID)
-	return c.rdb.Del(ctx, slotKey).Err()
+	key := accountSlotKey(accountID)
+	return c.rdb.ZRem(ctx, key, requestID).Err()
 }

 func (c *concurrencyCache) GetAccountConcurrency(ctx context.Context, accountID int64) (int, error) {
-	pattern := accountSlotPattern(accountID)
-	result, err := getCountScript.Run(ctx, c.rdb, []string{pattern}).Int()
+	key := accountSlotKey(accountID)
+	// 时间戳在 Lua 脚本内使用 Redis TIME 命令获取
+	result, err := getCountScript.Run(ctx, c.rdb, []string{key}, c.slotTTLSeconds).Int()
 	if err != nil {
 		return 0, err
 	}
@@ -161,10 +185,9 @@ func (c *concurrencyCache) GetAccountConcurrency(ctx context.Context, accountID
 // User slot operations

 func (c *concurrencyCache) AcquireUserSlot(ctx context.Context, userID int64, maxConcurrency int, requestID string) (bool, error) {
-	pattern := userSlotPattern(userID)
-	slotKey := userSlotKey(userID, requestID)
-
-	result, err := acquireScript.Run(ctx, c.rdb, []string{pattern, slotKey}, maxConcurrency, int(slotTTL.Seconds())).Int()
+	key := userSlotKey(userID)
+	// 时间戳在 Lua 脚本内使用 Redis TIME 命令获取，确保多实例时钟一致
+	result, err := acquireScript.Run(ctx, c.rdb, []string{key}, maxConcurrency, c.slotTTLSeconds, requestID).Int()
 	if err != nil {
 		return false, err
 	}
@@ -172,13 +195,14 @@ func (c *concurrencyCache) AcquireUserSlot(ctx context.Context, userID int64, ma
 }

 func (c *concurrencyCache) ReleaseUserSlot(ctx context.Context, userID int64, requestID string) error {
-	slotKey := userSlotKey(userID, requestID)
-	return c.rdb.Del(ctx, slotKey).Err()
+	key := userSlotKey(userID)
+	return c.rdb.ZRem(ctx, key, requestID).Err()
 }

 func (c *concurrencyCache) GetUserConcurrency(ctx context.Context, userID int64) (int, error) {
-	pattern := userSlotPattern(userID)
-	result, err := getCountScript.Run(ctx, c.rdb, []string{pattern}).Int()
+	key := userSlotKey(userID)
+	// 时间戳在 Lua 脚本内使用 Redis TIME 命令获取
+	result, err := getCountScript.Run(ctx, c.rdb, []string{key}, c.slotTTLSeconds).Int()
 	if err != nil {
 		return 0, err
 	}
@@ -189,7 +213,7 @@ func (c *concurrencyCache) GetUserConcurrency(ctx context.Context, userID int64)

 func (c *concurrencyCache) IncrementWaitCount(ctx context.Context, userID int64, maxWait int) (bool, error) {
 	key := waitQueueKey(userID)
-	result, err := incrementWaitScript.Run(ctx, c.rdb, []string{key}, maxWait, int(slotTTL.Seconds())).Int()
+	result, err := incrementWaitScript.Run(ctx, c.rdb, []string{key}, maxWait, c.slotTTLSeconds).Int()
 	if err != nil {
 		return false, err
 	}
--- a/backend/internal/repository/concurrency_cache_benchmark_test.go
+++ b/backend/internal/repository/concurrency_cache_benchmark_test.go
@@ -0,0 +1,135 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// 基准测试用 TTL 配置
+const benchSlotTTLMinutes = 15
+
+var benchSlotTTL = time.Duration(benchSlotTTLMinutes) * time.Minute
+
+// BenchmarkAccountConcurrency 用于对比 SCAN 与有序集合的计数性能。
+func BenchmarkAccountConcurrency(b *testing.B) {
+	rdb := newBenchmarkRedisClient(b)
+	defer func() {
+		_ = rdb.Close()
+	}()
+
+	cache := NewConcurrencyCache(rdb, benchSlotTTLMinutes).(*concurrencyCache)
+	ctx := context.Background()
+
+	for _, size := range []int{10, 100, 1000} {
+		size := size
+		b.Run(fmt.Sprintf("zset/slots=%d", size), func(b *testing.B) {
+			accountID := time.Now().UnixNano()
+			key := accountSlotKey(accountID)
+
+			b.StopTimer()
+			members := make([]redis.Z, 0, size)
+			now := float64(time.Now().Unix())
+			for i := 0; i < size; i++ {
+				members = append(members, redis.Z{
+					Score:  now,
+					Member: fmt.Sprintf("req_%d", i),
+				})
+			}
+			if err := rdb.ZAdd(ctx, key, members...).Err(); err != nil {
+				b.Fatalf("初始化有序集合失败: %v", err)
+			}
+			if err := rdb.Expire(ctx, key, benchSlotTTL).Err(); err != nil {
+				b.Fatalf("设置有序集合 TTL 失败: %v", err)
+			}
+			b.StartTimer()
+
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				if _, err := cache.GetAccountConcurrency(ctx, accountID); err != nil {
+					b.Fatalf("获取并发数量失败: %v", err)
+				}
+			}
+
+			b.StopTimer()
+			if err := rdb.Del(ctx, key).Err(); err != nil {
+				b.Fatalf("清理有序集合失败: %v", err)
+			}
+		})
+
+		b.Run(fmt.Sprintf("scan/slots=%d", size), func(b *testing.B) {
+			accountID := time.Now().UnixNano()
+			pattern := fmt.Sprintf("%s%d:*", accountSlotKeyPrefix, accountID)
+			keys := make([]string, 0, size)
+
+			b.StopTimer()
+			pipe := rdb.Pipeline()
+			for i := 0; i < size; i++ {
+				key := fmt.Sprintf("%s%d:req_%d", accountSlotKeyPrefix, accountID, i)
+				keys = append(keys, key)
+				pipe.Set(ctx, key, "1", benchSlotTTL)
+			}
+			if _, err := pipe.Exec(ctx); err != nil {
+				b.Fatalf("初始化扫描键失败: %v", err)
+			}
+			b.StartTimer()
+
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				if _, err := scanSlotCount(ctx, rdb, pattern); err != nil {
+					b.Fatalf("SCAN 计数失败: %v", err)
+				}
+			}
+
+			b.StopTimer()
+			if err := rdb.Del(ctx, keys...).Err(); err != nil {
+				b.Fatalf("清理扫描键失败: %v", err)
+			}
+		})
+	}
+}
+
+func scanSlotCount(ctx context.Context, rdb *redis.Client, pattern string) (int, error) {
+	var cursor uint64
+	count := 0
+	for {
+		keys, nextCursor, err := rdb.Scan(ctx, cursor, pattern, 100).Result()
+		if err != nil {
+			return 0, err
+		}
+		count += len(keys)
+		if nextCursor == 0 {
+			break
+		}
+		cursor = nextCursor
+	}
+	return count, nil
+}
+
+func newBenchmarkRedisClient(b *testing.B) *redis.Client {
+	b.Helper()
+
+	redisURL := os.Getenv("TEST_REDIS_URL")
+	if redisURL == "" {
+		b.Skip("未设置 TEST_REDIS_URL，跳过 Redis 基准测试")
+	}
+
+	opt, err := redis.ParseURL(redisURL)
+	if err != nil {
+		b.Fatalf("解析 TEST_REDIS_URL 失败: %v", err)
+	}
+
+	client := redis.NewClient(opt)
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	if err := client.Ping(ctx).Err(); err != nil {
+		b.Fatalf("Redis 连接失败: %v", err)
+	}
+
+	return client
+}
--- a/backend/internal/repository/concurrency_cache_integration_test.go
+++ b/backend/internal/repository/concurrency_cache_integration_test.go
@@ -14,6 +14,12 @@ import (
 	"github.com/stretchr/testify/suite"
 )

+// 测试用 TTL 配置（15 分钟，与默认值一致）
+const testSlotTTLMinutes = 15
+
+// 测试用 TTL Duration，用于 TTL 断言
+var testSlotTTL = time.Duration(testSlotTTLMinutes) * time.Minute
+
 type ConcurrencyCacheSuite struct {
 	IntegrationRedisSuite
 	cache service.ConcurrencyCache
@@ -21,7 +27,7 @@ type ConcurrencyCacheSuite struct {

 func (s *ConcurrencyCacheSuite) SetupTest() {
 	s.IntegrationRedisSuite.SetupTest()
-	s.cache = NewConcurrencyCache(s.rdb)
+	s.cache = NewConcurrencyCache(s.rdb, testSlotTTLMinutes)
 }

 func (s *ConcurrencyCacheSuite) TestAccountSlot_AcquireAndRelease() {
@@ -54,7 +60,7 @@ func (s *ConcurrencyCacheSuite) TestAccountSlot_AcquireAndRelease() {
 func (s *ConcurrencyCacheSuite) TestAccountSlot_TTL() {
 	accountID := int64(11)
 	reqID := "req_ttl_test"
-	slotKey := fmt.Sprintf("%s%d:%s", accountSlotKeyPrefix, accountID, reqID)
+	slotKey := fmt.Sprintf("%s%d", accountSlotKeyPrefix, accountID)

 	ok, err := s.cache.AcquireAccountSlot(s.ctx, accountID, 5, reqID)
 	require.NoError(s.T(), err, "AcquireAccountSlot")
@@ -62,7 +68,7 @@ func (s *ConcurrencyCacheSuite) TestAccountSlot_TTL() {

 	ttl, err := s.rdb.TTL(s.ctx, slotKey).Result()
 	require.NoError(s.T(), err, "TTL")
-	s.AssertTTLWithin(ttl, 1*time.Second, slotTTL)
+	s.AssertTTLWithin(ttl, 1*time.Second, testSlotTTL)
 }

 func (s *ConcurrencyCacheSuite) TestAccountSlot_DuplicateReqID() {
@@ -139,7 +145,7 @@ func (s *ConcurrencyCacheSuite) TestUserSlot_AcquireAndRelease() {
 func (s *ConcurrencyCacheSuite) TestUserSlot_TTL() {
 	userID := int64(200)
 	reqID := "req_ttl_test"
-	slotKey := fmt.Sprintf("%s%d:%s", userSlotKeyPrefix, userID, reqID)
+	slotKey := fmt.Sprintf("%s%d", userSlotKeyPrefix, userID)

 	ok, err := s.cache.AcquireUserSlot(s.ctx, userID, 5, reqID)
 	require.NoError(s.T(), err, "AcquireUserSlot")
@@ -147,7 +153,7 @@ func (s *ConcurrencyCacheSuite) TestUserSlot_TTL() {

 	ttl, err := s.rdb.TTL(s.ctx, slotKey).Result()
 	require.NoError(s.T(), err, "TTL")
-	s.AssertTTLWithin(ttl, 1*time.Second, slotTTL)
+	s.AssertTTLWithin(ttl, 1*time.Second, testSlotTTL)
 }

 func (s *ConcurrencyCacheSuite) TestWaitQueue_IncrementAndDecrement() {
@@ -168,7 +174,7 @@ func (s *ConcurrencyCacheSuite) TestWaitQueue_IncrementAndDecrement() {

 	ttl, err := s.rdb.TTL(s.ctx, waitKey).Result()
 	require.NoError(s.T(), err, "TTL waitKey")
-	s.AssertTTLWithin(ttl, 1*time.Second, slotTTL)
+	s.AssertTTLWithin(ttl, 1*time.Second, testSlotTTL)

 	require.NoError(s.T(), s.cache.DecrementWaitCount(s.ctx, userID), "DecrementWaitCount")

--- a/backend/internal/repository/gemini_oauth_client.go
+++ b/backend/internal/repository/gemini_oauth_client.go
@@ -109,9 +109,8 @@ func (c *geminiOAuthClient) RefreshToken(ctx context.Context, oauthType, refresh
 }

 func createGeminiReqClient(proxyURL string) *req.Client {
-	client := req.C().SetTimeout(60 * time.Second)
-	if proxyURL != "" {
-		client.SetProxyURL(proxyURL)
-	}
-	return client
+	return getSharedReqClient(reqClientOptions{
+		ProxyURL: proxyURL,
+		Timeout:  60 * time.Second,
+	})
 }
--- a/backend/internal/repository/geminicli_codeassist_client.go
+++ b/backend/internal/repository/geminicli_codeassist_client.go
@@ -76,11 +76,10 @@ func (c *geminiCliCodeAssistClient) OnboardUser(ctx context.Context, accessToken
 }

 func createGeminiCliReqClient(proxyURL string) *req.Client {
-	client := req.C().SetTimeout(30 * time.Second)
-	if proxyURL != "" {
-		client.SetProxyURL(proxyURL)
-	}
-	return client
+	return getSharedReqClient(reqClientOptions{
+		ProxyURL: proxyURL,
+		Timeout:  30 * time.Second,
+	})
 }

 func defaultLoadCodeAssistRequest() *geminicli.LoadCodeAssistRequest {
--- a/backend/internal/repository/github_release_service.go
+++ b/backend/internal/repository/github_release_service.go
@@ -9,6 +9,7 @@ import (
 	"os"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

@@ -17,10 +18,14 @@ type githubReleaseClient struct {
 }

 func NewGitHubReleaseClient() service.GitHubReleaseClient {
+	sharedClient, err := httpclient.GetClient(httpclient.Options{
+		Timeout: 30 * time.Second,
+	})
+	if err != nil {
+		sharedClient = &http.Client{Timeout: 30 * time.Second}
+	}
 	return &githubReleaseClient{
-		httpClient: &http.Client{
-			Timeout: 30 * time.Second,
-		},
+		httpClient: sharedClient,
 	}
 }

@@ -58,8 +63,13 @@ func (c *githubReleaseClient) DownloadFile(ctx context.Context, url, dest string
 		return err
 	}

-	client := &http.Client{Timeout: 10 * time.Minute}
-	resp, err := client.Do(req)
+	downloadClient, err := httpclient.GetClient(httpclient.Options{
+		Timeout: 10 * time.Minute,
+	})
+	if err != nil {
+		downloadClient = &http.Client{Timeout: 10 * time.Minute}
+	}
+	resp, err := downloadClient.Do(req)
 	if err != nil {
 		return err
 	}
--- a/backend/internal/repository/http_upstream.go
+++ b/backend/internal/repository/http_upstream.go
@@ -3,65 +3,104 @@ package repository
 import (
 	"net/http"
 	"net/url"
+	"strings"
+	"sync"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

-// httpUpstreamService is a generic HTTP upstream service that can be used for
-// making requests to any HTTP API (Claude, OpenAI, etc.) with optional proxy support.
+// httpUpstreamService 通用 HTTP 上游服务
+// 用于向任意 HTTP API（Claude、OpenAI 等）发送请求，支持可选代理
+//
+// 性能优化：
+// 1. 使用 sync.Map 缓存代理客户端实例，避免每次请求都创建新的 http.Client
+// 2. 复用 Transport 连接池，减少 TCP 握手和 TLS 协商开销
+// 3. 原实现每次请求都 new 一个 http.Client，导致连接无法复用
 type httpUpstreamService struct {
+	// defaultClient: 无代理时使用的默认客户端（单例复用）
 	defaultClient *http.Client
-	cfg           *config.Config
+	// proxyClients: 按代理 URL 缓存的客户端池，避免重复创建
+	proxyClients sync.Map
+	cfg          *config.Config
 }

-// NewHTTPUpstream creates a new generic HTTP upstream service
+// NewHTTPUpstream 创建通用 HTTP 上游服务
+// 使用配置中的连接池参数构建 Transport
 func NewHTTPUpstream(cfg *config.Config) service.HTTPUpstream {
-	responseHeaderTimeout := time.Duration(cfg.Gateway.ResponseHeaderTimeout) * time.Second
-	if responseHeaderTimeout == 0 {
-		responseHeaderTimeout = 300 * time.Second
-	}
-
-	transport := &http.Transport{
-		MaxIdleConns:          100,
-		MaxIdleConnsPerHost:   10,
-		IdleConnTimeout:       90 * time.Second,
-		ResponseHeaderTimeout: responseHeaderTimeout,
-	}
-
 	return &httpUpstreamService{
-		defaultClient: &http.Client{Transport: transport},
+		defaultClient: &http.Client{Transport: buildUpstreamTransport(cfg, nil)},
 		cfg:           cfg,
 	}
 }

 func (s *httpUpstreamService) Do(req *http.Request, proxyURL string) (*http.Response, error) {
-	if proxyURL == "" {
+	if strings.TrimSpace(proxyURL) == "" {
 		return s.defaultClient.Do(req)
 	}
-	client := s.createProxyClient(proxyURL)
+	client := s.getOrCreateClient(proxyURL)
 	return client.Do(req)
 }

-func (s *httpUpstreamService) createProxyClient(proxyURL string) *http.Client {
+// getOrCreateClient 获取或创建代理客户端
+// 性能优化：使用 sync.Map 实现无锁缓存，相同代理 URL 复用同一客户端
+// LoadOrStore 保证并发安全，避免重复创建
+func (s *httpUpstreamService) getOrCreateClient(proxyURL string) *http.Client {
+	proxyURL = strings.TrimSpace(proxyURL)
+	if proxyURL == "" {
+		return s.defaultClient
+	}
+	// 优先从缓存获取，命中则直接返回
+	if cached, ok := s.proxyClients.Load(proxyURL); ok {
+		return cached.(*http.Client)
+	}
+
 	parsedURL, err := url.Parse(proxyURL)
 	if err != nil {
 		return s.defaultClient
 	}

-	responseHeaderTimeout := time.Duration(s.cfg.Gateway.ResponseHeaderTimeout) * time.Second
-	if responseHeaderTimeout == 0 {
+	// 创建新客户端并缓存，LoadOrStore 保证只有一个实例被存储
+	client := &http.Client{Transport: buildUpstreamTransport(s.cfg, parsedURL)}
+	actual, _ := s.proxyClients.LoadOrStore(proxyURL, client)
+	return actual.(*http.Client)
+}
+
+// buildUpstreamTransport 构建上游请求的 Transport
+// 使用配置文件中的连接池参数，支持生产环境调优
+func buildUpstreamTransport(cfg *config.Config, proxyURL *url.URL) *http.Transport {
+	// 读取配置，使用合理的默认值
+	maxIdleConns := cfg.Gateway.MaxIdleConns
+	if maxIdleConns <= 0 {
+		maxIdleConns = 240
+	}
+	maxIdleConnsPerHost := cfg.Gateway.MaxIdleConnsPerHost
+	if maxIdleConnsPerHost <= 0 {
+		maxIdleConnsPerHost = 120
+	}
+	maxConnsPerHost := cfg.Gateway.MaxConnsPerHost
+	if maxConnsPerHost < 0 {
+		maxConnsPerHost = 240
+	}
+	idleConnTimeout := time.Duration(cfg.Gateway.IdleConnTimeoutSeconds) * time.Second
+	if idleConnTimeout <= 0 {
+		idleConnTimeout = 300 * time.Second
+	}
+	responseHeaderTimeout := time.Duration(cfg.Gateway.ResponseHeaderTimeout) * time.Second
+	if responseHeaderTimeout <= 0 {
 		responseHeaderTimeout = 300 * time.Second
 	}

 	transport := &http.Transport{
-		Proxy:                 http.ProxyURL(parsedURL),
-		MaxIdleConns:          100,
-		MaxIdleConnsPerHost:   10,
-		IdleConnTimeout:       90 * time.Second,
+		MaxIdleConns:          maxIdleConns,        // 最大空闲连接总数
+		MaxIdleConnsPerHost:   maxIdleConnsPerHost, // 每主机最大空闲连接
+		MaxConnsPerHost:       maxConnsPerHost,     // 每主机最大连接数（含活跃）
+		IdleConnTimeout:       idleConnTimeout,     // 空闲连接超时
 		ResponseHeaderTimeout: responseHeaderTimeout,
 	}
-
-	return &http.Client{Transport: transport}
+	if proxyURL != nil {
+		transport.Proxy = http.ProxyURL(proxyURL)
+	}
+	return transport
 }
--- a/backend/internal/repository/http_upstream_benchmark_test.go
+++ b/backend/internal/repository/http_upstream_benchmark_test.go
@@ -0,0 +1,46 @@
+package repository
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+)
+
+var httpClientSink *http.Client
+
+// BenchmarkHTTPUpstreamProxyClient 对比重复创建与复用代理客户端的开销。
+func BenchmarkHTTPUpstreamProxyClient(b *testing.B) {
+	cfg := &config.Config{
+		Gateway: config.GatewayConfig{ResponseHeaderTimeout: 300},
+	}
+	upstream := NewHTTPUpstream(cfg)
+	svc, ok := upstream.(*httpUpstreamService)
+	if !ok {
+		b.Fatalf("类型断言失败，无法获取 httpUpstreamService")
+	}
+
+	proxyURL := "http://127.0.0.1:8080"
+	b.ReportAllocs()
+
+	b.Run("新建", func(b *testing.B) {
+		parsedProxy, err := url.Parse(proxyURL)
+		if err != nil {
+			b.Fatalf("解析代理地址失败: %v", err)
+		}
+		for i := 0; i < b.N; i++ {
+			httpClientSink = &http.Client{
+				Transport: buildUpstreamTransport(cfg, parsedProxy),
+			}
+		}
+	})
+
+	b.Run("复用", func(b *testing.B) {
+		client := svc.getOrCreateClient(proxyURL)
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			httpClientSink = client
+		}
+	})
+}
--- a/backend/internal/repository/http_upstream_test.go
+++ b/backend/internal/repository/http_upstream_test.go
@@ -40,13 +40,13 @@ func (s *HTTPUpstreamSuite) TestCustomResponseHeaderTimeout() {
 	require.Equal(s.T(), 7*time.Second, transport.ResponseHeaderTimeout, "ResponseHeaderTimeout mismatch")
 }

-func (s *HTTPUpstreamSuite) TestCreateProxyClient_InvalidURLFallsBackToDefault() {
+func (s *HTTPUpstreamSuite) TestGetOrCreateClient_InvalidURLFallsBackToDefault() {
 	s.cfg.Gateway = config.GatewayConfig{ResponseHeaderTimeout: 5}
 	up := NewHTTPUpstream(s.cfg)
 	svc, ok := up.(*httpUpstreamService)
 	require.True(s.T(), ok, "expected *httpUpstreamService")

-	got := svc.createProxyClient("://bad-proxy-url")
+	got := svc.getOrCreateClient("://bad-proxy-url")
 	require.Equal(s.T(), svc.defaultClient, got, "expected defaultClient fallback")
 }

--- a/backend/internal/repository/openai_oauth_service.go
+++ b/backend/internal/repository/openai_oauth_service.go
@@ -82,12 +82,8 @@ func (s *openaiOAuthService) RefreshToken(ctx context.Context, refreshToken, pro
 }

 func createOpenAIReqClient(proxyURL string) *req.Client {
-	client := req.C().
-		SetTimeout(60 * time.Second)
-
-	if proxyURL != "" {
-		client.SetProxyURL(proxyURL)
-	}
-
-	return client
+	return getSharedReqClient(reqClientOptions{
+		ProxyURL: proxyURL,
+		Timeout:  60 * time.Second,
+	})
 }
--- a/backend/internal/repository/pricing_service.go
+++ b/backend/internal/repository/pricing_service.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

@@ -16,10 +17,14 @@ type pricingRemoteClient struct {
 }

 func NewPricingRemoteClient() service.PricingRemoteClient {
+	sharedClient, err := httpclient.GetClient(httpclient.Options{
+		Timeout: 30 * time.Second,
+	})
+	if err != nil {
+		sharedClient = &http.Client{Timeout: 30 * time.Second}
+	}
 	return &pricingRemoteClient{
-		httpClient: &http.Client{
-			Timeout: 30 * time.Second,
-		},
+		httpClient: sharedClient,
 	}
 }

--- a/backend/internal/repository/proxy_probe_service.go
+++ b/backend/internal/repository/proxy_probe_service.go
@@ -2,18 +2,14 @@ package repository

 import (
 	"context"
-	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"io"
-	"net"
 	"net/http"
-	"net/url"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
-
-	"golang.org/x/net/proxy"
 )

 func NewProxyExitInfoProber() service.ProxyExitInfoProber {
@@ -27,14 +23,14 @@ type proxyProbeService struct {
 }

 func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*service.ProxyExitInfo, int64, error) {
-	transport, err := createProxyTransport(proxyURL)
+	client, err := httpclient.GetClient(httpclient.Options{
+		ProxyURL:           proxyURL,
+		Timeout:            15 * time.Second,
+		InsecureSkipVerify: true,
+		ProxyStrict:        true,
+	})
 	if err != nil {
-		return nil, 0, fmt.Errorf("failed to create proxy transport: %w", err)
-	}
-
-	client := &http.Client{
-		Transport: transport,
-		Timeout:   15 * time.Second,
+		return nil, 0, fmt.Errorf("failed to create proxy client: %w", err)
 	}

 	startTime := time.Now()
@@ -78,31 +74,3 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 		Country: ipInfo.Country,
 	}, latencyMs, nil
 }
-
-func createProxyTransport(proxyURL string) (*http.Transport, error) {
-	parsedURL, err := url.Parse(proxyURL)
-	if err != nil {
-		return nil, fmt.Errorf("invalid proxy URL: %w", err)
-	}
-
-	transport := &http.Transport{
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-
-	switch parsedURL.Scheme {
-	case "http", "https":
-		transport.Proxy = http.ProxyURL(parsedURL)
-	case "socks5":
-		dialer, err := proxy.FromURL(parsedURL, proxy.Direct)
-		if err != nil {
-			return nil, fmt.Errorf("failed to create socks5 dialer: %w", err)
-		}
-		transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
-			return dialer.Dial(network, addr)
-		}
-	default:
-		return nil, fmt.Errorf("unsupported proxy protocol: %s", parsedURL.Scheme)
-	}
-
-	return transport, nil
-}
--- a/backend/internal/repository/proxy_probe_service_test.go
+++ b/backend/internal/repository/proxy_probe_service_test.go
@@ -34,22 +34,16 @@ func (s *ProxyProbeServiceSuite) setupProxyServer(handler http.HandlerFunc) {
 	s.proxySrv = httptest.NewServer(handler)
 }

-func (s *ProxyProbeServiceSuite) TestCreateProxyTransport_InvalidURL() {
-	_, err := createProxyTransport("://bad")
+func (s *ProxyProbeServiceSuite) TestProbeProxy_InvalidProxyURL() {
+	_, _, err := s.prober.ProbeProxy(s.ctx, "://bad")
 	require.Error(s.T(), err)
-	require.ErrorContains(s.T(), err, "invalid proxy URL")
+	require.ErrorContains(s.T(), err, "failed to create proxy client")
 }

-func (s *ProxyProbeServiceSuite) TestCreateProxyTransport_UnsupportedScheme() {
-	_, err := createProxyTransport("ftp://127.0.0.1:1")
+func (s *ProxyProbeServiceSuite) TestProbeProxy_UnsupportedProxyScheme() {
+	_, _, err := s.prober.ProbeProxy(s.ctx, "ftp://127.0.0.1:1")
 	require.Error(s.T(), err)
-	require.ErrorContains(s.T(), err, "unsupported proxy protocol")
-}
-
-func (s *ProxyProbeServiceSuite) TestCreateProxyTransport_Socks5SetsDialer() {
-	tr, err := createProxyTransport("socks5://127.0.0.1:1080")
-	require.NoError(s.T(), err, "createProxyTransport")
-	require.NotNil(s.T(), tr.DialContext, "expected DialContext to be set for socks5")
+	require.ErrorContains(s.T(), err, "failed to create proxy client")
 }

 func (s *ProxyProbeServiceSuite) TestProbeProxy_Success() {
--- a/backend/internal/repository/req_client_pool.go
+++ b/backend/internal/repository/req_client_pool.go
@@ -0,0 +1,59 @@
+package repository
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/imroc/req/v3"
+)
+
+// reqClientOptions 定义 req 客户端的构建参数
+type reqClientOptions struct {
+	ProxyURL    string        // 代理 URL（支持 http/https/socks5）
+	Timeout     time.Duration // 请求超时时间
+	Impersonate bool          // 是否模拟 Chrome 浏览器指纹
+}
+
+// sharedReqClients 存储按配置参数缓存的 req 客户端实例
+//
+// 性能优化说明：
+// 原实现在每次 OAuth 刷新时都创建新的 req.Client：
+// 1. claude_oauth_service.go: 每次刷新创建新客户端
+// 2. openai_oauth_service.go: 每次刷新创建新客户端
+// 3. gemini_oauth_client.go: 每次刷新创建新客户端
+//
+// 新实现使用 sync.Map 缓存客户端：
+// 1. 相同配置（代理+超时+模拟设置）复用同一客户端
+// 2. 复用底层连接池，减少 TLS 握手开销
+// 3. LoadOrStore 保证并发安全，避免重复创建
+var sharedReqClients sync.Map
+
+// getSharedReqClient 获取共享的 req 客户端实例
+// 性能优化：相同配置复用同一客户端，避免重复创建
+func getSharedReqClient(opts reqClientOptions) *req.Client {
+	key := buildReqClientKey(opts)
+	if cached, ok := sharedReqClients.Load(key); ok {
+		return cached.(*req.Client)
+	}
+
+	client := req.C().SetTimeout(opts.Timeout)
+	if opts.Impersonate {
+		client = client.ImpersonateChrome()
+	}
+	if strings.TrimSpace(opts.ProxyURL) != "" {
+		client.SetProxyURL(strings.TrimSpace(opts.ProxyURL))
+	}
+
+	actual, _ := sharedReqClients.LoadOrStore(key, client)
+	return actual.(*req.Client)
+}
+
+func buildReqClientKey(opts reqClientOptions) string {
+	return fmt.Sprintf("%s|%s|%t",
+		strings.TrimSpace(opts.ProxyURL),
+		opts.Timeout.String(),
+		opts.Impersonate,
+	)
+}
--- a/backend/internal/repository/turnstile_service.go
+++ b/backend/internal/repository/turnstile_service.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

@@ -20,11 +21,15 @@ type turnstileVerifier struct {
 }

 func NewTurnstileVerifier() service.TurnstileVerifier {
+	sharedClient, err := httpclient.GetClient(httpclient.Options{
+		Timeout: 10 * time.Second,
+	})
+	if err != nil {
+		sharedClient = &http.Client{Timeout: 10 * time.Second}
+	}
 	return &turnstileVerifier{
-		httpClient: &http.Client{
-			Timeout: 10 * time.Second,
-		},
-		verifyURL: turnstileVerifyURL,
+		httpClient: sharedClient,
+		verifyURL:  turnstileVerifyURL,
 	}
 }

--- a/backend/internal/repository/usage_log_repo.go
+++ b/backend/internal/repository/usage_log_repo.go
@@ -452,6 +452,161 @@ func (r *usageLogRepository) GetApiKeyStatsAggregated(ctx context.Context, apiKe
 	return &stats, nil
 }

+// GetAccountStatsAggregated 使用 SQL 聚合统计账号使用数据
+//
+// 性能优化说明：
+// 原实现先查询所有日志记录，再在应用层循环计算统计值：
+// 1. 需要传输大量数据到应用层
+// 2. 应用层循环计算增加 CPU 和内存开销
+//
+// 新实现使用 SQL 聚合函数：
+// 1. 在数据库层完成 COUNT/SUM/AVG 计算
+// 2. 只返回单行聚合结果，大幅减少数据传输量
+// 3. 利用数据库索引优化聚合查询性能
+func (r *usageLogRepository) GetAccountStatsAggregated(ctx context.Context, accountID int64, startTime, endTime time.Time) (*usagestats.UsageStats, error) {
+	query := `
+		SELECT
+			COUNT(*) as total_requests,
+			COALESCE(SUM(input_tokens), 0) as total_input_tokens,
+			COALESCE(SUM(output_tokens), 0) as total_output_tokens,
+			COALESCE(SUM(cache_creation_tokens + cache_read_tokens), 0) as total_cache_tokens,
+			COALESCE(SUM(total_cost), 0) as total_cost,
+			COALESCE(SUM(actual_cost), 0) as total_actual_cost,
+			COALESCE(AVG(COALESCE(duration_ms, 0)), 0) as avg_duration_ms
+		FROM usage_logs
+		WHERE account_id = $1 AND created_at >= $2 AND created_at < $3
+	`
+
+	var stats usagestats.UsageStats
+	if err := scanSingleRow(
+		ctx,
+		r.sql,
+		query,
+		[]any{accountID, startTime, endTime},
+		&stats.TotalRequests,
+		&stats.TotalInputTokens,
+		&stats.TotalOutputTokens,
+		&stats.TotalCacheTokens,
+		&stats.TotalCost,
+		&stats.TotalActualCost,
+		&stats.AverageDurationMs,
+	); err != nil {
+		return nil, err
+	}
+	stats.TotalTokens = stats.TotalInputTokens + stats.TotalOutputTokens + stats.TotalCacheTokens
+	return &stats, nil
+}
+
+// GetModelStatsAggregated 使用 SQL 聚合统计模型使用数据
+// 性能优化：数据库层聚合计算，避免应用层循环统计
+func (r *usageLogRepository) GetModelStatsAggregated(ctx context.Context, modelName string, startTime, endTime time.Time) (*usagestats.UsageStats, error) {
+	query := `
+		SELECT
+			COUNT(*) as total_requests,
+			COALESCE(SUM(input_tokens), 0) as total_input_tokens,
+			COALESCE(SUM(output_tokens), 0) as total_output_tokens,
+			COALESCE(SUM(cache_creation_tokens + cache_read_tokens), 0) as total_cache_tokens,
+			COALESCE(SUM(total_cost), 0) as total_cost,
+			COALESCE(SUM(actual_cost), 0) as total_actual_cost,
+			COALESCE(AVG(COALESCE(duration_ms, 0)), 0) as avg_duration_ms
+		FROM usage_logs
+		WHERE model = $1 AND created_at >= $2 AND created_at < $3
+	`
+
+	var stats usagestats.UsageStats
+	if err := scanSingleRow(
+		ctx,
+		r.sql,
+		query,
+		[]any{modelName, startTime, endTime},
+		&stats.TotalRequests,
+		&stats.TotalInputTokens,
+		&stats.TotalOutputTokens,
+		&stats.TotalCacheTokens,
+		&stats.TotalCost,
+		&stats.TotalActualCost,
+		&stats.AverageDurationMs,
+	); err != nil {
+		return nil, err
+	}
+	stats.TotalTokens = stats.TotalInputTokens + stats.TotalOutputTokens + stats.TotalCacheTokens
+	return &stats, nil
+}
+
+// GetDailyStatsAggregated 使用 SQL 聚合统计用户的每日使用数据
+// 性能优化：使用 GROUP BY 在数据库层按日期分组聚合，避免应用层循环分组统计
+func (r *usageLogRepository) GetDailyStatsAggregated(ctx context.Context, userID int64, startTime, endTime time.Time) (result []map[string]any, err error) {
+	query := `
+		SELECT
+			TO_CHAR(created_at, 'YYYY-MM-DD') as date,
+			COUNT(*) as total_requests,
+			COALESCE(SUM(input_tokens), 0) as total_input_tokens,
+			COALESCE(SUM(output_tokens), 0) as total_output_tokens,
+			COALESCE(SUM(cache_creation_tokens + cache_read_tokens), 0) as total_cache_tokens,
+			COALESCE(SUM(total_cost), 0) as total_cost,
+			COALESCE(SUM(actual_cost), 0) as total_actual_cost,
+			COALESCE(AVG(COALESCE(duration_ms, 0)), 0) as avg_duration_ms
+		FROM usage_logs
+		WHERE user_id = $1 AND created_at >= $2 AND created_at < $3
+		GROUP BY 1
+		ORDER BY 1
+	`
+
+	rows, err := r.sql.QueryContext(ctx, query, userID, startTime, endTime)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if closeErr := rows.Close(); closeErr != nil && err == nil {
+			err = closeErr
+			result = nil
+		}
+	}()
+
+	result = make([]map[string]any, 0)
+	for rows.Next() {
+		var (
+			date              string
+			totalRequests     int64
+			totalInputTokens  int64
+			totalOutputTokens int64
+			totalCacheTokens  int64
+			totalCost         float64
+			totalActualCost   float64
+			avgDurationMs     float64
+		)
+		if err = rows.Scan(
+			&date,
+			&totalRequests,
+			&totalInputTokens,
+			&totalOutputTokens,
+			&totalCacheTokens,
+			&totalCost,
+			&totalActualCost,
+			&avgDurationMs,
+		); err != nil {
+			return nil, err
+		}
+		result = append(result, map[string]any{
+			"date":                date,
+			"total_requests":      totalRequests,
+			"total_input_tokens":  totalInputTokens,
+			"total_output_tokens": totalOutputTokens,
+			"total_cache_tokens":  totalCacheTokens,
+			"total_tokens":        totalInputTokens + totalOutputTokens + totalCacheTokens,
+			"total_cost":          totalCost,
+			"total_actual_cost":   totalActualCost,
+			"average_duration_ms": avgDurationMs,
+		})
+	}
+
+	if err = rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}
+
 func (r *usageLogRepository) ListByApiKeyAndTimeRange(ctx context.Context, apiKeyID int64, startTime, endTime time.Time) ([]service.UsageLog, *pagination.PaginationResult, error) {
 	query := "SELECT " + usageLogSelectColumns + " FROM usage_logs WHERE api_key_id = $1 AND created_at >= $2 AND created_at < $3 ORDER BY id DESC"
 	logs, err := r.queryUsageLogs(ctx, query, apiKeyID, startTime, endTime)
--- a/backend/internal/repository/wire.go
+++ b/backend/internal/repository/wire.go
@@ -1,9 +1,18 @@
 package repository

 import (
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/service"
 	"github.com/google/wire"
+	"github.com/redis/go-redis/v9"
 )

+// ProvideConcurrencyCache 创建并发控制缓存，从配置读取 TTL 参数
+// 性能优化：TTL 可配置，支持长时间运行的 LLM 请求场景
+func ProvideConcurrencyCache(rdb *redis.Client, cfg *config.Config) service.ConcurrencyCache {
+	return NewConcurrencyCache(rdb, cfg.Gateway.ConcurrencySlotTTLMinutes)
+}
+
 // ProviderSet is the Wire provider set for all repositories
 var ProviderSet = wire.NewSet(
 	NewUserRepository,
@@ -20,7 +29,7 @@ var ProviderSet = wire.NewSet(
 	NewGatewayCache,
 	NewBillingCache,
 	NewApiKeyCache,
-	NewConcurrencyCache,
+	ProvideConcurrencyCache,
 	NewEmailCache,
 	NewIdentityCache,
 	NewRedeemCache,
--- a/backend/internal/server/api_contract_test.go
+++ b/backend/internal/server/api_contract_test.go
@@ -981,6 +981,18 @@ func (r *stubUsageLogRepo) GetApiKeyStatsAggregated(ctx context.Context, apiKeyI
 	return nil, errors.New("not implemented")
 }

+func (r *stubUsageLogRepo) GetAccountStatsAggregated(ctx context.Context, accountID int64, startTime, endTime time.Time) (*usagestats.UsageStats, error) {
+	return nil, errors.New("not implemented")
+}
+
+func (r *stubUsageLogRepo) GetModelStatsAggregated(ctx context.Context, modelName string, startTime, endTime time.Time) (*usagestats.UsageStats, error) {
+	return nil, errors.New("not implemented")
+}
+
+func (r *stubUsageLogRepo) GetDailyStatsAggregated(ctx context.Context, userID int64, startTime, endTime time.Time) ([]map[string]any, error) {
+	return nil, errors.New("not implemented")
+}
+
 func (r *stubUsageLogRepo) GetBatchUserUsageStats(ctx context.Context, userIDs []int64) (map[int64]*usagestats.BatchUserUsageStats, error) {
 	return nil, errors.New("not implemented")
 }
--- a/backend/internal/server/middleware/request_body_limit.go
+++ b/backend/internal/server/middleware/request_body_limit.go
@@ -0,0 +1,15 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+// RequestBodyLimit 使用 MaxBytesReader 限制请求体大小。
+func RequestBodyLimit(maxBytes int64) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, maxBytes)
+		c.Next()
+	}
+}
--- a/backend/internal/server/routes/gateway.go
+++ b/backend/internal/server/routes/gateway.go
@@ -18,8 +18,11 @@ func RegisterGatewayRoutes(
 	subscriptionService *service.SubscriptionService,
 	cfg *config.Config,
 ) {
+	bodyLimit := middleware.RequestBodyLimit(cfg.Gateway.MaxBodySize)
+
 	// API网关（Claude API兼容）
 	gateway := r.Group("/v1")
+	gateway.Use(bodyLimit)
 	gateway.Use(gin.HandlerFunc(apiKeyAuth))
 	{
 		gateway.POST("/messages", h.Gateway.Messages)
@@ -32,6 +35,7 @@ func RegisterGatewayRoutes(

 	// Gemini 原生 API 兼容层（Gemini SDK/CLI 直连）
 	gemini := r.Group("/v1beta")
+	gemini.Use(bodyLimit)
 	gemini.Use(middleware.ApiKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
 	{
 		gemini.GET("/models", h.Gateway.GeminiV1BetaListModels)
@@ -41,10 +45,11 @@ func RegisterGatewayRoutes(
 	}

 	// OpenAI Responses API（不带v1前缀的别名）
-	r.POST("/responses", gin.HandlerFunc(apiKeyAuth), h.OpenAIGateway.Responses)
+	r.POST("/responses", bodyLimit, gin.HandlerFunc(apiKeyAuth), h.OpenAIGateway.Responses)

 	// Antigravity 专用路由（仅使用 antigravity 账户，不混合调度）
 	antigravityV1 := r.Group("/antigravity/v1")
+	antigravityV1.Use(bodyLimit)
 	antigravityV1.Use(middleware.ForcePlatform(service.PlatformAntigravity))
 	antigravityV1.Use(gin.HandlerFunc(apiKeyAuth))
 	{
@@ -55,6 +60,7 @@ func RegisterGatewayRoutes(
 	}

 	antigravityV1Beta := r.Group("/antigravity/v1beta")
+	antigravityV1Beta.Use(bodyLimit)
 	antigravityV1Beta.Use(middleware.ForcePlatform(service.PlatformAntigravity))
 	antigravityV1Beta.Use(middleware.ApiKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
 	{
--- a/backend/internal/service/account_usage_service.go
+++ b/backend/internal/service/account_usage_service.go
@@ -52,6 +52,9 @@ type UsageLogRepository interface {
 	// Aggregated stats (optimized)
 	GetUserStatsAggregated(ctx context.Context, userID int64, startTime, endTime time.Time) (*usagestats.UsageStats, error)
 	GetApiKeyStatsAggregated(ctx context.Context, apiKeyID int64, startTime, endTime time.Time) (*usagestats.UsageStats, error)
+	GetAccountStatsAggregated(ctx context.Context, accountID int64, startTime, endTime time.Time) (*usagestats.UsageStats, error)
+	GetModelStatsAggregated(ctx context.Context, modelName string, startTime, endTime time.Time) (*usagestats.UsageStats, error)
+	GetDailyStatsAggregated(ctx context.Context, userID int64, startTime, endTime time.Time) ([]map[string]any, error)
 }

 // apiUsageCache 缓存从 Anthropic API 获取的使用率数据（utilization, resets_at）
--- a/backend/internal/service/billing_cache_service.go
+++ b/backend/internal/service/billing_cache_service.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"sync"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/config"
@@ -27,6 +28,45 @@ type subscriptionCacheData struct {
 	Version      int64
 }

+// 缓存写入任务类型
+type cacheWriteKind int
+
+const (
+	cacheWriteSetBalance cacheWriteKind = iota
+	cacheWriteSetSubscription
+	cacheWriteUpdateSubscriptionUsage
+	cacheWriteDeductBalance
+)
+
+// 异步缓存写入工作池配置
+//
+// 性能优化说明：
+// 原实现在请求热路径中使用 goroutine 异步更新缓存，存在以下问题：
+// 1. 每次请求创建新 goroutine，高并发下产生大量短生命周期 goroutine
+// 2. 无法控制并发数量，可能导致 Redis 连接耗尽
+// 3. goroutine 创建/销毁带来额外开销
+//
+// 新实现使用固定大小的工作池：
+// 1. 预创建 10 个 worker goroutine，避免频繁创建销毁
+// 2. 使用带缓冲的 channel（1000）作为任务队列，平滑写入峰值
+// 3. 非阻塞写入，队列满时丢弃任务（缓存最终一致性可接受）
+// 4. 统一超时控制，避免慢操作阻塞工作池
+const (
+	cacheWriteWorkerCount = 10              // 工作协程数量
+	cacheWriteBufferSize  = 1000            // 任务队列缓冲大小
+	cacheWriteTimeout     = 2 * time.Second // 单个写入操作超时
+)
+
+// cacheWriteTask 缓存写入任务
+type cacheWriteTask struct {
+	kind             cacheWriteKind
+	userID           int64
+	groupID          int64
+	balance          float64
+	amount           float64
+	subscriptionData *subscriptionCacheData
+}
+
 // BillingCacheService 计费缓存服务
 // 负责余额和订阅数据的缓存管理，提供高性能的计费资格检查
 type BillingCacheService struct {
@@ -34,16 +74,81 @@ type BillingCacheService struct {
 	userRepo UserRepository
 	subRepo  UserSubscriptionRepository
 	cfg      *config.Config
+
+	cacheWriteChan     chan cacheWriteTask
+	cacheWriteWg       sync.WaitGroup
+	cacheWriteStopOnce sync.Once
 }

 // NewBillingCacheService 创建计费缓存服务
 func NewBillingCacheService(cache BillingCache, userRepo UserRepository, subRepo UserSubscriptionRepository, cfg *config.Config) *BillingCacheService {
-	return &BillingCacheService{
+	svc := &BillingCacheService{
 		cache:    cache,
 		userRepo: userRepo,
 		subRepo:  subRepo,
 		cfg:      cfg,
 	}
+	svc.startCacheWriteWorkers()
+	return svc
+}
+
+// Stop 关闭缓存写入工作池
+func (s *BillingCacheService) Stop() {
+	s.cacheWriteStopOnce.Do(func() {
+		if s.cacheWriteChan == nil {
+			return
+		}
+		close(s.cacheWriteChan)
+		s.cacheWriteWg.Wait()
+		s.cacheWriteChan = nil
+	})
+}
+
+func (s *BillingCacheService) startCacheWriteWorkers() {
+	s.cacheWriteChan = make(chan cacheWriteTask, cacheWriteBufferSize)
+	for i := 0; i < cacheWriteWorkerCount; i++ {
+		s.cacheWriteWg.Add(1)
+		go s.cacheWriteWorker()
+	}
+}
+
+func (s *BillingCacheService) enqueueCacheWrite(task cacheWriteTask) {
+	if s.cacheWriteChan == nil {
+		return
+	}
+	defer func() {
+		_ = recover()
+	}()
+	select {
+	case s.cacheWriteChan <- task:
+	default:
+	}
+}
+
+func (s *BillingCacheService) cacheWriteWorker() {
+	defer s.cacheWriteWg.Done()
+	for task := range s.cacheWriteChan {
+		ctx, cancel := context.WithTimeout(context.Background(), cacheWriteTimeout)
+		switch task.kind {
+		case cacheWriteSetBalance:
+			s.setBalanceCache(ctx, task.userID, task.balance)
+		case cacheWriteSetSubscription:
+			s.setSubscriptionCache(ctx, task.userID, task.groupID, task.subscriptionData)
+		case cacheWriteUpdateSubscriptionUsage:
+			if s.cache != nil {
+				if err := s.cache.UpdateSubscriptionUsage(ctx, task.userID, task.groupID, task.amount); err != nil {
+					log.Printf("Warning: update subscription cache failed for user %d group %d: %v", task.userID, task.groupID, err)
+				}
+			}
+		case cacheWriteDeductBalance:
+			if s.cache != nil {
+				if err := s.cache.DeductUserBalance(ctx, task.userID, task.amount); err != nil {
+					log.Printf("Warning: deduct balance cache failed for user %d: %v", task.userID, err)
+				}
+			}
+		}
+		cancel()
+	}
 }

 // ============================================
@@ -70,11 +175,11 @@ func (s *BillingCacheService) GetUserBalance(ctx context.Context, userID int64)
 	}

 	// 异步建立缓存
-	go func() {
-		cacheCtx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
-		defer cancel()
-		s.setBalanceCache(cacheCtx, userID, balance)
-	}()
+	s.enqueueCacheWrite(cacheWriteTask{
+		kind:    cacheWriteSetBalance,
+		userID:  userID,
+		balance: balance,
+	})

 	return balance, nil
 }
@@ -98,7 +203,7 @@ func (s *BillingCacheService) setBalanceCache(ctx context.Context, userID int64,
 	}
 }

-// DeductBalanceCache 扣减余额缓存（异步调用，用于扣费后更新缓存）
+// DeductBalanceCache 扣减余额缓存（同步调用）
 func (s *BillingCacheService) DeductBalanceCache(ctx context.Context, userID int64, amount float64) error {
 	if s.cache == nil {
 		return nil
@@ -106,6 +211,15 @@ func (s *BillingCacheService) DeductBalanceCache(ctx context.Context, userID int
 	return s.cache.DeductUserBalance(ctx, userID, amount)
 }

+// QueueDeductBalance 异步扣减余额缓存
+func (s *BillingCacheService) QueueDeductBalance(userID int64, amount float64) {
+	s.enqueueCacheWrite(cacheWriteTask{
+		kind:   cacheWriteDeductBalance,
+		userID: userID,
+		amount: amount,
+	})
+}
+
 // InvalidateUserBalance 失效用户余额缓存
 func (s *BillingCacheService) InvalidateUserBalance(ctx context.Context, userID int64) error {
 	if s.cache == nil {
@@ -141,11 +255,12 @@ func (s *BillingCacheService) GetSubscriptionStatus(ctx context.Context, userID,
 	}

 	// 异步建立缓存
-	go func() {
-		cacheCtx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
-		defer cancel()
-		s.setSubscriptionCache(cacheCtx, userID, groupID, data)
-	}()
+	s.enqueueCacheWrite(cacheWriteTask{
+		kind:             cacheWriteSetSubscription,
+		userID:           userID,
+		groupID:          groupID,
+		subscriptionData: data,
+	})

 	return data, nil
 }
@@ -199,7 +314,7 @@ func (s *BillingCacheService) setSubscriptionCache(ctx context.Context, userID,
 	}
 }

-// UpdateSubscriptionUsage 更新订阅用量缓存（异步调用，用于扣费后更新缓存）
+// UpdateSubscriptionUsage 更新订阅用量缓存（同步调用）
 func (s *BillingCacheService) UpdateSubscriptionUsage(ctx context.Context, userID, groupID int64, costUSD float64) error {
 	if s.cache == nil {
 		return nil
@@ -207,6 +322,16 @@ func (s *BillingCacheService) UpdateSubscriptionUsage(ctx context.Context, userI
 	return s.cache.UpdateSubscriptionUsage(ctx, userID, groupID, costUSD)
 }

+// QueueUpdateSubscriptionUsage 异步更新订阅用量缓存
+func (s *BillingCacheService) QueueUpdateSubscriptionUsage(userID, groupID int64, costUSD float64) {
+	s.enqueueCacheWrite(cacheWriteTask{
+		kind:    cacheWriteUpdateSubscriptionUsage,
+		userID:  userID,
+		groupID: groupID,
+		amount:  costUSD,
+	})
+}
+
 // InvalidateSubscription 失效指定订阅缓存
 func (s *BillingCacheService) InvalidateSubscription(ctx context.Context, userID, groupID int64) error {
 	if s.cache == nil {
--- a/backend/internal/service/billing_cache_service_test.go
+++ b/backend/internal/service/billing_cache_service_test.go
@@ -0,0 +1,75 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+)
+
+type billingCacheWorkerStub struct {
+	balanceUpdates      int64
+	subscriptionUpdates int64
+}
+
+func (b *billingCacheWorkerStub) GetUserBalance(ctx context.Context, userID int64) (float64, error) {
+	return 0, errors.New("not implemented")
+}
+
+func (b *billingCacheWorkerStub) SetUserBalance(ctx context.Context, userID int64, balance float64) error {
+	atomic.AddInt64(&b.balanceUpdates, 1)
+	return nil
+}
+
+func (b *billingCacheWorkerStub) DeductUserBalance(ctx context.Context, userID int64, amount float64) error {
+	atomic.AddInt64(&b.balanceUpdates, 1)
+	return nil
+}
+
+func (b *billingCacheWorkerStub) InvalidateUserBalance(ctx context.Context, userID int64) error {
+	return nil
+}
+
+func (b *billingCacheWorkerStub) GetSubscriptionCache(ctx context.Context, userID, groupID int64) (*SubscriptionCacheData, error) {
+	return nil, errors.New("not implemented")
+}
+
+func (b *billingCacheWorkerStub) SetSubscriptionCache(ctx context.Context, userID, groupID int64, data *SubscriptionCacheData) error {
+	atomic.AddInt64(&b.subscriptionUpdates, 1)
+	return nil
+}
+
+func (b *billingCacheWorkerStub) UpdateSubscriptionUsage(ctx context.Context, userID, groupID int64, cost float64) error {
+	atomic.AddInt64(&b.subscriptionUpdates, 1)
+	return nil
+}
+
+func (b *billingCacheWorkerStub) InvalidateSubscriptionCache(ctx context.Context, userID, groupID int64) error {
+	return nil
+}
+
+func TestBillingCacheServiceQueueHighLoad(t *testing.T) {
+	cache := &billingCacheWorkerStub{}
+	svc := NewBillingCacheService(cache, nil, nil, &config.Config{})
+	t.Cleanup(svc.Stop)
+
+	start := time.Now()
+	for i := 0; i < cacheWriteBufferSize*2; i++ {
+		svc.QueueDeductBalance(1, 1)
+	}
+	require.Less(t, time.Since(start), 2*time.Second)
+
+	svc.QueueUpdateSubscriptionUsage(1, 2, 1.5)
+
+	require.Eventually(t, func() bool {
+		return atomic.LoadInt64(&cache.balanceUpdates) > 0
+	}, 2*time.Second, 10*time.Millisecond)
+
+	require.Eventually(t, func() bool {
+		return atomic.LoadInt64(&cache.subscriptionUpdates) > 0
+	}, 2*time.Second, 10*time.Millisecond)
+}
--- a/backend/internal/service/concurrency_service.go
+++ b/backend/internal/service/concurrency_service.go
@@ -9,22 +9,22 @@ import (
 	"time"
 )

-// ConcurrencyCache defines cache operations for concurrency service
-// Uses independent keys per request slot with native Redis TTL for automatic cleanup
+// ConcurrencyCache 定义并发控制的缓存接口
+// 使用有序集合存储槽位，按时间戳清理过期条目
 type ConcurrencyCache interface {
-	// Account slot management - each slot is a separate key with independent TTL
-	// Key format: concurrency:account:{accountID}:{requestID}
+	// 账号槽位管理
+	// 键格式: concurrency:account:{accountID}（有序集合，成员为 requestID）
 	AcquireAccountSlot(ctx context.Context, accountID int64, maxConcurrency int, requestID string) (bool, error)
 	ReleaseAccountSlot(ctx context.Context, accountID int64, requestID string) error
 	GetAccountConcurrency(ctx context.Context, accountID int64) (int, error)

-	// User slot management - each slot is a separate key with independent TTL
-	// Key format: concurrency:user:{userID}:{requestID}
+	// 用户槽位管理
+	// 键格式: concurrency:user:{userID}（有序集合，成员为 requestID）
 	AcquireUserSlot(ctx context.Context, userID int64, maxConcurrency int, requestID string) (bool, error)
 	ReleaseUserSlot(ctx context.Context, userID int64, requestID string) error
 	GetUserConcurrency(ctx context.Context, userID int64) (int, error)

-	// Wait queue - uses counter with TTL set only on creation
+	// 等待队列计数（只在首次创建时设置 TTL）
 	IncrementWaitCount(ctx context.Context, userID int64, maxWait int) (bool, error)
 	DecrementWaitCount(ctx context.Context, userID int64) error
 }
--- a/backend/internal/service/crs_sync_service.go
+++ b/backend/internal/service/crs_sync_service.go
@@ -12,6 +12,8 @@ import (
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 )

 type CRSSyncService struct {
@@ -193,7 +195,12 @@ func (s *CRSSyncService) SyncFromCRS(ctx context.Context, input SyncFromCRSInput
 		return nil, errors.New("username and password are required")
 	}

-	client := &http.Client{Timeout: 20 * time.Second}
+	client, err := httpclient.GetClient(httpclient.Options{
+		Timeout: 20 * time.Second,
+	})
+	if err != nil {
+		client = &http.Client{Timeout: 20 * time.Second}
+	}

 	adminToken, err := crsLogin(ctx, client, baseURL, input.Username, input.Password)
 	if err != nil {
--- a/backend/internal/service/gateway_request.go
+++ b/backend/internal/service/gateway_request.go
@@ -0,0 +1,70 @@
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// ParsedRequest 保存网关请求的预解析结果
+//
+// 性能优化说明：
+// 原实现在多个位置重复解析请求体（Handler、Service 各解析一次）：
+// 1. gateway_handler.go 解析获取 model 和 stream
+// 2. gateway_service.go 再次解析获取 system、messages、metadata
+// 3. GenerateSessionHash 又一次解析获取会话哈希所需字段
+//
+// 新实现一次解析，多处复用：
+// 1. 在 Handler 层统一调用 ParseGatewayRequest 一次性解析
+// 2. 将解析结果 ParsedRequest 传递给 Service 层
+// 3. 避免重复 json.Unmarshal，减少 CPU 和内存开销
+type ParsedRequest struct {
+	Body           []byte // 原始请求体（保留用于转发）
+	Model          string // 请求的模型名称
+	Stream         bool   // 是否为流式请求
+	MetadataUserID string // metadata.user_id（用于会话亲和）
+	System         any    // system 字段内容
+	Messages       []any  // messages 数组
+	HasSystem      bool   // 是否包含 system 字段
+}
+
+// ParseGatewayRequest 解析网关请求体并返回结构化结果
+// 性能优化：一次解析提取所有需要的字段，避免重复 Unmarshal
+func ParseGatewayRequest(body []byte) (*ParsedRequest, error) {
+	var req map[string]any
+	if err := json.Unmarshal(body, &req); err != nil {
+		return nil, err
+	}
+
+	parsed := &ParsedRequest{
+		Body: body,
+	}
+
+	if rawModel, exists := req["model"]; exists {
+		model, ok := rawModel.(string)
+		if !ok {
+			return nil, fmt.Errorf("invalid model field type")
+		}
+		parsed.Model = model
+	}
+	if rawStream, exists := req["stream"]; exists {
+		stream, ok := rawStream.(bool)
+		if !ok {
+			return nil, fmt.Errorf("invalid stream field type")
+		}
+		parsed.Stream = stream
+	}
+	if metadata, ok := req["metadata"].(map[string]any); ok {
+		if userID, ok := metadata["user_id"].(string); ok {
+			parsed.MetadataUserID = userID
+		}
+	}
+	if system, ok := req["system"]; ok && system != nil {
+		parsed.HasSystem = true
+		parsed.System = system
+	}
+	if messages, ok := req["messages"].([]any); ok {
+		parsed.Messages = messages
+	}
+
+	return parsed, nil
+}
--- a/backend/internal/service/gateway_request_test.go
+++ b/backend/internal/service/gateway_request_test.go
@@ -0,0 +1,38 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseGatewayRequest(t *testing.T) {
+	body := []byte(`{"model":"claude-3-7-sonnet","stream":true,"metadata":{"user_id":"session_123e4567-e89b-12d3-a456-426614174000"},"system":[{"type":"text","text":"hello","cache_control":{"type":"ephemeral"}}],"messages":[{"content":"hi"}]}`)
+	parsed, err := ParseGatewayRequest(body)
+	require.NoError(t, err)
+	require.Equal(t, "claude-3-7-sonnet", parsed.Model)
+	require.True(t, parsed.Stream)
+	require.Equal(t, "session_123e4567-e89b-12d3-a456-426614174000", parsed.MetadataUserID)
+	require.True(t, parsed.HasSystem)
+	require.NotNil(t, parsed.System)
+	require.Len(t, parsed.Messages, 1)
+}
+
+func TestParseGatewayRequest_SystemNull(t *testing.T) {
+	body := []byte(`{"model":"claude-3","system":null}`)
+	parsed, err := ParseGatewayRequest(body)
+	require.NoError(t, err)
+	require.False(t, parsed.HasSystem)
+}
+
+func TestParseGatewayRequest_InvalidModelType(t *testing.T) {
+	body := []byte(`{"model":123}`)
+	_, err := ParseGatewayRequest(body)
+	require.Error(t, err)
+}
+
+func TestParseGatewayRequest_InvalidStreamType(t *testing.T) {
+	body := []byte(`{"stream":"true"}`)
+	_, err := ParseGatewayRequest(body)
+	require.Error(t, err)
+}
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -19,7 +19,6 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
-	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"

 	"github.com/gin-gonic/gin"
@@ -33,7 +32,10 @@ const (

 // sseDataRe matches SSE data lines with optional whitespace after colon.
 // Some upstream APIs return non-standard "data:" without space (should be "data: ").
-var sseDataRe = regexp.MustCompile(`^data:\s*`)
+var (
+	sseDataRe      = regexp.MustCompile(`^data:\s*`)
+	sessionIDRegex = regexp.MustCompile(`session_([a-f0-9-]{36})`)
+)

 // allowedHeaders 白名单headers（参考CRS项目）
 var allowedHeaders = map[string]bool{
@@ -141,40 +143,36 @@ func NewGatewayService(
 	}
 }

-// GenerateSessionHash 从请求体计算粘性会话hash
-func (s *GatewayService) GenerateSessionHash(body []byte) string {
-	var req map[string]any
-	if err := json.Unmarshal(body, &req); err != nil {
+// GenerateSessionHash 从预解析请求计算粘性会话 hash
+func (s *GatewayService) GenerateSessionHash(parsed *ParsedRequest) string {
+	if parsed == nil {
 		return ""
 	}

-	// 1. 最高优先级：从metadata.user_id提取session_xxx
-	if metadata, ok := req["metadata"].(map[string]any); ok {
-		if userID, ok := metadata["user_id"].(string); ok {
-			re := regexp.MustCompile(`session_([a-f0-9-]{36})`)
-			if match := re.FindStringSubmatch(userID); len(match) > 1 {
-				return match[1]
-			}
+	// 1. 最高优先级：从 metadata.user_id 提取 session_xxx
+	if parsed.MetadataUserID != "" {
+		if match := sessionIDRegex.FindStringSubmatch(parsed.MetadataUserID); len(match) > 1 {
+			return match[1]
 		}
 	}

-	// 2. 提取带cache_control: {type: "ephemeral"}的内容
-	cacheableContent := s.extractCacheableContent(req)
+	// 2. 提取带 cache_control: {type: "ephemeral"} 的内容
+	cacheableContent := s.extractCacheableContent(parsed)
 	if cacheableContent != "" {
 		return s.hashContent(cacheableContent)
 	}

-	// 3. Fallback: 使用system内容
-	if system := req["system"]; system != nil {
-		systemText := s.extractTextFromSystem(system)
+	// 3. Fallback: 使用 system 内容
+	if parsed.System != nil {
+		systemText := s.extractTextFromSystem(parsed.System)
 		if systemText != "" {
 			return s.hashContent(systemText)
 		}
 	}

-	// 4. 最后fallback: 使用第一条消息
-	if messages, ok := req["messages"].([]any); ok && len(messages) > 0 {
-		if firstMsg, ok := messages[0].(map[string]any); ok {
+	// 4. 最后 fallback: 使用第一条消息
+	if len(parsed.Messages) > 0 {
+		if firstMsg, ok := parsed.Messages[0].(map[string]any); ok {
 			msgText := s.extractTextFromContent(firstMsg["content"])
 			if msgText != "" {
 				return s.hashContent(msgText)
@@ -185,36 +183,38 @@ func (s *GatewayService) GenerateSessionHash(body []byte) string {
 	return ""
 }

-func (s *GatewayService) extractCacheableContent(req map[string]any) string {
-	var content string
+func (s *GatewayService) extractCacheableContent(parsed *ParsedRequest) string {
+	if parsed == nil {
+		return ""
+	}

-	// 检查system中的cacheable内容
-	if system, ok := req["system"].([]any); ok {
+	var builder strings.Builder
+
+	// 检查 system 中的 cacheable 内容
+	if system, ok := parsed.System.([]any); ok {
 		for _, part := range system {
 			if partMap, ok := part.(map[string]any); ok {
 				if cc, ok := partMap["cache_control"].(map[string]any); ok {
 					if cc["type"] == "ephemeral" {
 						if text, ok := partMap["text"].(string); ok {
-							content += text
+							builder.WriteString(text)
 						}
 					}
 				}
 			}
 		}
 	}
+	systemText := builder.String()

-	// 检查messages中的cacheable内容
-	if messages, ok := req["messages"].([]any); ok {
-		for _, msg := range messages {
-			if msgMap, ok := msg.(map[string]any); ok {
-				if msgContent, ok := msgMap["content"].([]any); ok {
-					for _, part := range msgContent {
-						if partMap, ok := part.(map[string]any); ok {
-							if cc, ok := partMap["cache_control"].(map[string]any); ok {
-								if cc["type"] == "ephemeral" {
-									// 找到cacheable内容，提取第一条消息的文本
-									return s.extractTextFromContent(msgMap["content"])
-								}
+	// 检查 messages 中的 cacheable 内容
+	for _, msg := range parsed.Messages {
+		if msgMap, ok := msg.(map[string]any); ok {
+			if msgContent, ok := msgMap["content"].([]any); ok {
+				for _, part := range msgContent {
+					if partMap, ok := part.(map[string]any); ok {
+						if cc, ok := partMap["cache_control"].(map[string]any); ok {
+							if cc["type"] == "ephemeral" {
+								return s.extractTextFromContent(msgMap["content"])
 							}
 						}
 					}
@@ -223,7 +223,7 @@ func (s *GatewayService) extractCacheableContent(req map[string]any) string {
 		}
 	}

-	return content
+	return systemText
 }

 func (s *GatewayService) extractTextFromSystem(system any) string {
@@ -588,19 +588,17 @@ func (s *GatewayService) shouldFailoverUpstreamError(statusCode int) bool {
 }

 // Forward 转发请求到Claude API
-func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *Account, body []byte) (*ForwardResult, error) {
+func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *Account, parsed *ParsedRequest) (*ForwardResult, error) {
 	startTime := time.Now()
-
-	// 解析请求获取model和stream
-	var req struct {
-		Model  string `json:"model"`
-		Stream bool   `json:"stream"`
-	}
-	if err := json.Unmarshal(body, &req); err != nil {
-		return nil, fmt.Errorf("parse request: %w", err)
+	if parsed == nil {
+		return nil, fmt.Errorf("parse request: empty request")
 	}

-	if !gjson.GetBytes(body, "system").Exists() {
+	body := parsed.Body
+	reqModel := parsed.Model
+	reqStream := parsed.Stream
+
+	if !parsed.HasSystem {
 		body, _ = sjson.SetBytes(body, "system", []any{
 			map[string]any{
 				"type": "text",
@@ -613,13 +611,13 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 	}

 	// 应用模型映射（仅对apikey类型账号）
-	originalModel := req.Model
+	originalModel := reqModel
 	if account.Type == AccountTypeApiKey {
-		mappedModel := account.GetMappedModel(req.Model)
-		if mappedModel != req.Model {
+		mappedModel := account.GetMappedModel(reqModel)
+		if mappedModel != reqModel {
 			// 替换请求体中的模型名
 			body = s.replaceModelInBody(body, mappedModel)
-			req.Model = mappedModel
+			reqModel = mappedModel
 			log.Printf("Model mapping applied: %s -> %s (account: %s)", originalModel, mappedModel, account.Name)
 		}
 	}
@@ -640,7 +638,7 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 	var resp *http.Response
 	for attempt := 1; attempt <= maxRetries; attempt++ {
 		// 构建上游请求（每次重试需要重新构建，因为请求体需要重新读取）
-		upstreamReq, err := s.buildUpstreamRequest(ctx, c, account, body, token, tokenType)
+		upstreamReq, err := s.buildUpstreamRequest(ctx, c, account, body, token, tokenType, reqModel)
 		if err != nil {
 			return nil, err
 		}
@@ -692,8 +690,8 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 	// 处理正常响应
 	var usage *ClaudeUsage
 	var firstTokenMs *int
-	if req.Stream {
-		streamResult, err := s.handleStreamingResponse(ctx, resp, c, account, startTime, originalModel, req.Model)
+	if reqStream {
+		streamResult, err := s.handleStreamingResponse(ctx, resp, c, account, startTime, originalModel, reqModel)
 		if err != nil {
 			if err.Error() == "have error in stream" {
 				return nil, &UpstreamFailoverError{
@@ -705,7 +703,7 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 		usage = streamResult.usage
 		firstTokenMs = streamResult.firstTokenMs
 	} else {
-		usage, err = s.handleNonStreamingResponse(ctx, resp, c, account, originalModel, req.Model)
+		usage, err = s.handleNonStreamingResponse(ctx, resp, c, account, originalModel, reqModel)
 		if err != nil {
 			return nil, err
 		}
@@ -715,13 +713,13 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 		RequestID:    resp.Header.Get("x-request-id"),
 		Usage:        *usage,
 		Model:        originalModel, // 使用原始模型用于计费和日志
-		Stream:       req.Stream,
+		Stream:       reqStream,
 		Duration:     time.Since(startTime),
 		FirstTokenMs: firstTokenMs,
 	}, nil
 }

-func (s *GatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token, tokenType string) (*http.Request, error) {
+func (s *GatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token, tokenType, modelID string) (*http.Request, error) {
 	// 确定目标URL
 	targetURL := claudeAPIURL
 	if account.Type == AccountTypeApiKey {
@@ -787,7 +785,7 @@ func (s *GatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Contex

 	// 处理anthropic-beta header（OAuth账号需要特殊处理）
 	if tokenType == "oauth" {
-		req.Header.Set("anthropic-beta", s.getBetaHeader(body, c.GetHeader("anthropic-beta")))
+		req.Header.Set("anthropic-beta", s.getBetaHeader(modelID, c.GetHeader("anthropic-beta")))
 	}

 	return req, nil
@@ -795,7 +793,7 @@ func (s *GatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Contex

 // getBetaHeader 处理anthropic-beta header
 // 对于OAuth账号，需要确保包含oauth-2025-04-20
-func (s *GatewayService) getBetaHeader(body []byte, clientBetaHeader string) string {
+func (s *GatewayService) getBetaHeader(modelID string, clientBetaHeader string) string {
 	// 如果客户端传了anthropic-beta
 	if clientBetaHeader != "" {
 		// 已包含oauth beta则直接返回
@@ -832,15 +830,7 @@ func (s *GatewayService) getBetaHeader(body []byte, clientBetaHeader string) str
 	}

 	// 客户端没传，根据模型生成
-	var modelID string
-	var reqMap map[string]any
-	if json.Unmarshal(body, &reqMap) == nil {
-		if m, ok := reqMap["model"].(string); ok {
-			modelID = m
-		}
-	}
-
-	// haiku模型不需要claude-code beta
+	// haiku 模型不需要 claude-code beta
 	if strings.Contains(strings.ToLower(modelID), "haiku") {
 		return claude.HaikuBetaHeader
 	}
@@ -1248,13 +1238,7 @@ func (s *GatewayService) RecordUsage(ctx context.Context, input *RecordUsageInpu
 				log.Printf("Increment subscription usage failed: %v", err)
 			}
 			// 异步更新订阅缓存
-			go func() {
-				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-				defer cancel()
-				if err := s.billingCacheService.UpdateSubscriptionUsage(cacheCtx, user.ID, *apiKey.GroupID, cost.TotalCost); err != nil {
-					log.Printf("Update subscription cache failed: %v", err)
-				}
-			}()
+			s.billingCacheService.QueueUpdateSubscriptionUsage(user.ID, *apiKey.GroupID, cost.TotalCost)
 		}
 	} else {
 		// 余额模式：扣除用户余额（使用 ActualCost 考虑倍率后的费用）
@@ -1263,13 +1247,7 @@ func (s *GatewayService) RecordUsage(ctx context.Context, input *RecordUsageInpu
 				log.Printf("Deduct balance failed: %v", err)
 			}
 			// 异步更新余额缓存
-			go func() {
-				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-				defer cancel()
-				if err := s.billingCacheService.DeductBalanceCache(cacheCtx, user.ID, cost.ActualCost); err != nil {
-					log.Printf("Update balance cache failed: %v", err)
-				}
-			}()
+			s.billingCacheService.QueueDeductBalance(user.ID, cost.ActualCost)
 		}
 	}

@@ -1281,7 +1259,15 @@ func (s *GatewayService) RecordUsage(ctx context.Context, input *RecordUsageInpu

 // ForwardCountTokens 转发 count_tokens 请求到上游 API
 // 特点：不记录使用量、仅支持非流式响应
-func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context, account *Account, body []byte) error {
+func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context, account *Account, parsed *ParsedRequest) error {
+	if parsed == nil {
+		s.countTokensError(c, http.StatusBadRequest, "invalid_request_error", "Request body is empty")
+		return fmt.Errorf("parse request: empty request")
+	}
+
+	body := parsed.Body
+	reqModel := parsed.Model
+
 	// Antigravity 账户不支持 count_tokens 转发，返回估算值
 	// 参考 Antigravity-Manager 和 proxycast 实现
 	if account.Platform == PlatformAntigravity {
@@ -1291,14 +1277,12 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,

 	// 应用模型映射（仅对 apikey 类型账号）
 	if account.Type == AccountTypeApiKey {
-		var req struct {
-			Model string `json:"model"`
-		}
-		if err := json.Unmarshal(body, &req); err == nil && req.Model != "" {
-			mappedModel := account.GetMappedModel(req.Model)
-			if mappedModel != req.Model {
+		if reqModel != "" {
+			mappedModel := account.GetMappedModel(reqModel)
+			if mappedModel != reqModel {
 				body = s.replaceModelInBody(body, mappedModel)
-				log.Printf("CountTokens model mapping applied: %s -> %s (account: %s)", req.Model, mappedModel, account.Name)
+				reqModel = mappedModel
+				log.Printf("CountTokens model mapping applied: %s -> %s (account: %s)", parsed.Model, mappedModel, account.Name)
 			}
 		}
 	}
@@ -1311,7 +1295,7 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 	}

 	// 构建上游请求
-	upstreamReq, err := s.buildCountTokensRequest(ctx, c, account, body, token, tokenType)
+	upstreamReq, err := s.buildCountTokensRequest(ctx, c, account, body, token, tokenType, reqModel)
 	if err != nil {
 		s.countTokensError(c, http.StatusInternalServerError, "api_error", "Failed to build request")
 		return err
@@ -1363,7 +1347,7 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 }

 // buildCountTokensRequest 构建 count_tokens 上游请求
-func (s *GatewayService) buildCountTokensRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token, tokenType string) (*http.Request, error) {
+func (s *GatewayService) buildCountTokensRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token, tokenType, modelID string) (*http.Request, error) {
 	// 确定目标 URL
 	targetURL := claudeAPICountTokensURL
 	if account.Type == AccountTypeApiKey {
@@ -1424,7 +1408,7 @@ func (s *GatewayService) buildCountTokensRequest(ctx context.Context, c *gin.Con

 	// OAuth 账号：处理 anthropic-beta header
 	if tokenType == "oauth" {
-		req.Header.Set("anthropic-beta", s.getBetaHeader(body, c.GetHeader("anthropic-beta")))
+		req.Header.Set("anthropic-beta", s.getBetaHeader(modelID, c.GetHeader("anthropic-beta")))
 	}

 	return req, nil
--- a/backend/internal/service/gateway_service_benchmark_test.go
+++ b/backend/internal/service/gateway_service_benchmark_test.go
@@ -0,0 +1,50 @@
+package service
+
+import (
+	"strconv"
+	"testing"
+)
+
+var benchmarkStringSink string
+
+// BenchmarkGenerateSessionHash_Metadata 关注 JSON 解析与正则匹配开销。
+func BenchmarkGenerateSessionHash_Metadata(b *testing.B) {
+	svc := &GatewayService{}
+	body := []byte(`{"metadata":{"user_id":"session_123e4567-e89b-12d3-a456-426614174000"},"messages":[{"content":"hello"}]}`)
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		parsed, err := ParseGatewayRequest(body)
+		if err != nil {
+			b.Fatalf("解析请求失败: %v", err)
+		}
+		benchmarkStringSink = svc.GenerateSessionHash(parsed)
+	}
+}
+
+// BenchmarkExtractCacheableContent_System 关注字符串拼接路径的性能。
+func BenchmarkExtractCacheableContent_System(b *testing.B) {
+	svc := &GatewayService{}
+	req := buildSystemCacheableRequest(12)
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		benchmarkStringSink = svc.extractCacheableContent(req)
+	}
+}
+
+func buildSystemCacheableRequest(parts int) *ParsedRequest {
+	systemParts := make([]any, 0, parts)
+	for i := 0; i < parts; i++ {
+		systemParts = append(systemParts, map[string]any{
+			"text": "system_part_" + strconv.Itoa(i),
+			"cache_control": map[string]any{
+				"type": "ephemeral",
+			},
+		})
+	}
+	return &ParsedRequest{
+		System:    systemParts,
+		HasSystem: true,
+	}
+}
--- a/backend/internal/service/gemini_messages_compat_service.go
+++ b/backend/internal/service/gemini_messages_compat_service.go
@@ -921,7 +921,10 @@ func sleepGeminiBackoff(attempt int) {
 	time.Sleep(sleepFor)
 }

-var sensitiveQueryParamRegex = regexp.MustCompile(`(?i)([?&](?:key|client_secret|access_token|refresh_token)=)[^&"\s]+`)
+var (
+	sensitiveQueryParamRegex = regexp.MustCompile(`(?i)([?&](?:key|client_secret|access_token|refresh_token)=)[^&"\s]+`)
+	retryInRegex             = regexp.MustCompile(`Please retry in ([0-9.]+)s`)
+)

 func sanitizeUpstreamErrorMessage(msg string) string {
 	if msg == "" {
@@ -1925,7 +1928,6 @@ func ParseGeminiRateLimitResetTime(body []byte) *int64 {
 	}

 	// Match "Please retry in Xs"
-	retryInRegex := regexp.MustCompile(`Please retry in ([0-9.]+)s`)
 	matches := retryInRegex.FindStringSubmatch(string(body))
 	if len(matches) == 2 {
 		if dur, err := time.ParseDuration(matches[1] + "s"); err == nil {
--- a/backend/internal/service/gemini_oauth_service.go
+++ b/backend/internal/service/gemini_oauth_service.go
@@ -7,13 +7,13 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"strconv"
 	"strings"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/geminicli"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 )

 type GeminiOAuthService struct {
@@ -497,11 +497,12 @@ func fetchProjectIDFromResourceManager(ctx context.Context, accessToken, proxyUR
 	req.Header.Set("Authorization", "Bearer "+accessToken)
 	req.Header.Set("User-Agent", geminicli.GeminiCLIUserAgent)

-	client := &http.Client{Timeout: 30 * time.Second}
-	if strings.TrimSpace(proxyURL) != "" {
-		if proxyURLParsed, err := url.Parse(strings.TrimSpace(proxyURL)); err == nil {
-			client.Transport = &http.Transport{Proxy: http.ProxyURL(proxyURLParsed)}
-		}
+	client, err := httpclient.GetClient(httpclient.Options{
+		ProxyURL: strings.TrimSpace(proxyURL),
+		Timeout:  30 * time.Second,
+	})
+	if err != nil {
+		client = &http.Client{Timeout: 30 * time.Second}
 	}

 	resp, err := client.Do(req)
--- a/backend/internal/service/openai_gateway_service.go
+++ b/backend/internal/service/openai_gateway_service.go
@@ -768,20 +768,12 @@ func (s *OpenAIGatewayService) RecordUsage(ctx context.Context, input *OpenAIRec
 	if isSubscriptionBilling {
 		if cost.TotalCost > 0 {
 			_ = s.userSubRepo.IncrementUsage(ctx, subscription.ID, cost.TotalCost)
-			go func() {
-				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-				defer cancel()
-				_ = s.billingCacheService.UpdateSubscriptionUsage(cacheCtx, user.ID, *apiKey.GroupID, cost.TotalCost)
-			}()
+			s.billingCacheService.QueueUpdateSubscriptionUsage(user.ID, *apiKey.GroupID, cost.TotalCost)
 		}
 	} else {
 		if cost.ActualCost > 0 {
 			_ = s.userRepo.DeductBalance(ctx, user.ID, cost.ActualCost)
-			go func() {
-				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-				defer cancel()
-				_ = s.billingCacheService.DeductBalanceCache(cacheCtx, user.ID, cost.ActualCost)
-			}()
+			s.billingCacheService.QueueDeductBalance(user.ID, cost.ActualCost)
 		}
 	}

--- a/backend/internal/service/pricing_service.go
+++ b/backend/internal/service/pricing_service.go
@@ -18,6 +18,11 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 )

+var (
+	openAIModelDatePattern = regexp.MustCompile(`-\d{8}$`)
+	openAIModelBasePattern = regexp.MustCompile(`^(gpt-\d+(?:\.\d+)?)(?:-|$)`)
+)
+
 // LiteLLMModelPricing LiteLLM价格数据结构
 // 只保留我们需要的字段，使用指针来处理可能缺失的值
 type LiteLLMModelPricing struct {
@@ -595,11 +600,8 @@ func (s *PricingService) matchByModelFamily(model string) *LiteLLMModelPricing {
 // 2. gpt-5.2-20251222 -> gpt-5.2（去掉日期版本号）
 // 3. 最终回退到 DefaultTestModel (gpt-5.1-codex)
 func (s *PricingService) matchOpenAIModel(model string) *LiteLLMModelPricing {
-	// 正则匹配日期后缀 (如 -20251222)
-	datePattern := regexp.MustCompile(`-\d{8}$`)
-
 	// 尝试的回退变体
-	variants := s.generateOpenAIModelVariants(model, datePattern)
+	variants := s.generateOpenAIModelVariants(model, openAIModelDatePattern)

 	for _, variant := range variants {
 		if pricing, ok := s.pricingData[variant]; ok {
@@ -638,14 +640,13 @@ func (s *PricingService) generateOpenAIModelVariants(model string, datePattern *

 	// 2. 提取基础版本号: gpt-5.2-codex -> gpt-5.2
 	// 只匹配纯数字版本号格式 gpt-X 或 gpt-X.Y，不匹配 gpt-4o 这种带字母后缀的
-	basePattern := regexp.MustCompile(`^(gpt-\d+(?:\.\d+)?)(?:-|$)`)
-	if matches := basePattern.FindStringSubmatch(model); len(matches) > 1 {
+	if matches := openAIModelBasePattern.FindStringSubmatch(model); len(matches) > 1 {
 		addVariant(matches[1])
 	}

 	// 3. 同时去掉日期后再提取基础版本号
 	if withoutDate != model {
-		if matches := basePattern.FindStringSubmatch(withoutDate); len(matches) > 1 {
+		if matches := openAIModelBasePattern.FindStringSubmatch(withoutDate); len(matches) > 1 {
 			addVariant(matches[1])
 		}
 	}
--- a/backend/internal/service/usage_service.go
+++ b/backend/internal/service/usage_service.go
@@ -186,22 +186,40 @@ func (s *UsageService) GetStatsByApiKey(ctx context.Context, apiKeyID int64, sta

 // GetStatsByAccount 获取账号的使用统计
 func (s *UsageService) GetStatsByAccount(ctx context.Context, accountID int64, startTime, endTime time.Time) (*UsageStats, error) {
-	logs, _, err := s.usageRepo.ListByAccountAndTimeRange(ctx, accountID, startTime, endTime)
+	stats, err := s.usageRepo.GetAccountStatsAggregated(ctx, accountID, startTime, endTime)
 	if err != nil {
-		return nil, fmt.Errorf("list usage logs: %w", err)
+		return nil, fmt.Errorf("get account stats: %w", err)
 	}

-	return s.calculateStats(logs), nil
+	return &UsageStats{
+		TotalRequests:     stats.TotalRequests,
+		TotalInputTokens:  stats.TotalInputTokens,
+		TotalOutputTokens: stats.TotalOutputTokens,
+		TotalCacheTokens:  stats.TotalCacheTokens,
+		TotalTokens:       stats.TotalTokens,
+		TotalCost:         stats.TotalCost,
+		TotalActualCost:   stats.TotalActualCost,
+		AverageDurationMs: stats.AverageDurationMs,
+	}, nil
 }

 // GetStatsByModel 获取模型的使用统计
 func (s *UsageService) GetStatsByModel(ctx context.Context, modelName string, startTime, endTime time.Time) (*UsageStats, error) {
-	logs, _, err := s.usageRepo.ListByModelAndTimeRange(ctx, modelName, startTime, endTime)
+	stats, err := s.usageRepo.GetModelStatsAggregated(ctx, modelName, startTime, endTime)
 	if err != nil {
-		return nil, fmt.Errorf("list usage logs: %w", err)
+		return nil, fmt.Errorf("get model stats: %w", err)
 	}

-	return s.calculateStats(logs), nil
+	return &UsageStats{
+		TotalRequests:     stats.TotalRequests,
+		TotalInputTokens:  stats.TotalInputTokens,
+		TotalOutputTokens: stats.TotalOutputTokens,
+		TotalCacheTokens:  stats.TotalCacheTokens,
+		TotalTokens:       stats.TotalTokens,
+		TotalCost:         stats.TotalCost,
+		TotalActualCost:   stats.TotalActualCost,
+		AverageDurationMs: stats.AverageDurationMs,
+	}, nil
 }

 // GetDailyStats 获取每日使用统计（最近N天）
@@ -209,54 +227,12 @@ func (s *UsageService) GetDailyStats(ctx context.Context, userID int64, days int
 	endTime := time.Now()
 	startTime := endTime.AddDate(0, 0, -days)

-	logs, _, err := s.usageRepo.ListByUserAndTimeRange(ctx, userID, startTime, endTime)
+	stats, err := s.usageRepo.GetDailyStatsAggregated(ctx, userID, startTime, endTime)
 	if err != nil {
-		return nil, fmt.Errorf("list usage logs: %w", err)
+		return nil, fmt.Errorf("get daily stats: %w", err)
 	}

-	// 按日期分组统计
-	dailyStats := make(map[string]*UsageStats)
-	for _, log := range logs {
-		dateKey := log.CreatedAt.Format("2006-01-02")
-		if _, exists := dailyStats[dateKey]; !exists {
-			dailyStats[dateKey] = &UsageStats{}
-		}
-
-		stats := dailyStats[dateKey]
-		stats.TotalRequests++
-		stats.TotalInputTokens += int64(log.InputTokens)
-		stats.TotalOutputTokens += int64(log.OutputTokens)
-		stats.TotalCacheTokens += int64(log.CacheCreationTokens + log.CacheReadTokens)
-		stats.TotalTokens += int64(log.TotalTokens())
-		stats.TotalCost += log.TotalCost
-		stats.TotalActualCost += log.ActualCost
-
-		if log.DurationMs != nil {
-			stats.AverageDurationMs += float64(*log.DurationMs)
-		}
-	}
-
-	// 计算平均值并转换为数组
-	result := make([]map[string]any, 0, len(dailyStats))
-	for date, stats := range dailyStats {
-		if stats.TotalRequests > 0 {
-			stats.AverageDurationMs /= float64(stats.TotalRequests)
-		}
-
-		result = append(result, map[string]any{
-			"date":                date,
-			"total_requests":      stats.TotalRequests,
-			"total_input_tokens":  stats.TotalInputTokens,
-			"total_output_tokens": stats.TotalOutputTokens,
-			"total_cache_tokens":  stats.TotalCacheTokens,
-			"total_tokens":        stats.TotalTokens,
-			"total_cost":          stats.TotalCost,
-			"total_actual_cost":   stats.TotalActualCost,
-			"average_duration_ms": stats.AverageDurationMs,
-		})
-	}
-
-	return result, nil
+	return stats, nil
 }

 // calculateStats 计算统计数据
--- a/backend/migrations/010_add_usage_logs_aggregated_indexes.sql
+++ b/backend/migrations/010_add_usage_logs_aggregated_indexes.sql
@@ -0,0 +1,4 @@
+-- 为聚合查询补充复合索引
+CREATE INDEX IF NOT EXISTS idx_usage_logs_account_created_at ON usage_logs(account_id, created_at);
+CREATE INDEX IF NOT EXISTS idx_usage_logs_api_key_created_at ON usage_logs(api_key_id, created_at);
+CREATE INDEX IF NOT EXISTS idx_usage_logs_model_created_at ON usage_logs(model, created_at);