perf: 优化后端性能与直播延迟，包含数据库WAL模式、流媒体写缓冲、转码 Preset 优化、聊天锁和指标采集优化，以及前端自动追帧功能

backend/internal/chat/hub.go

@@ -66,20 +66,25 @@ func (h *Hub) Run() {
 			}
 			h.rooms[client.RoomID][client] = true
 
-			// Send existing history to the newly joined client
+			// Copy existing history to send outside the lock
+			var historyCopy []Message
 			if history, ok := h.roomsHistory[client.RoomID]; ok {
-				for _, msg := range history {
-					msg.IsHistory = true
-					msgBytes, _ := json.Marshal(msg)
-					// Use select to avoid blocking if client's send channel is full
+				historyCopy = make([]Message, len(history))
+				copy(historyCopy, history)
+			}
+			h.mutex.Unlock()
+
+			// Send history outside the lock
+			for _, msg := range historyCopy {
+				msg.IsHistory = true
+				msgBytes, err := json.Marshal(msg)
+				if err == nil {
 					select {
 					case client.Send <- msgBytes:
 					default:
-						// If send fails, we could potentially log or ignore
 					}
 				}
 			}
-			h.mutex.Unlock()
 
 		case client := <-h.unregister:
 			h.mutex.Lock()
@@ -99,6 +104,12 @@ func (h *Hub) Run() {
 			h.mutex.Unlock()
 
 		case message := <-h.broadcast:
+			// Marshal message outside the lock to optimize performance
+			msgBytes, err := json.Marshal(message)
+			if err != nil {
+				continue
+			}
+
 			h.mutex.Lock()
 			// Only store "chat" and "danmaku" messages in history
 			if message.Type == "chat" || message.Type == "danmaku" {
@@ -111,7 +122,6 @@ func (h *Hub) Run() {
 
 			clients := h.rooms[message.RoomID]
 			if clients != nil {
-				msgBytes, _ := json.Marshal(message)
 				for client := range clients {
 					select {
 					case client.Send <- msgBytes:

backend/internal/db/db.go

@@ -29,14 +29,23 @@ func InitDB() {
 	)
 
 	var err error
-	// Use SQLite database stored in a local file named "hightube.db"
-	DB, err = gorm.Open(sqlite.Open("hightube.db"), &gorm.Config{
+	// Use SQLite database stored in a local file named "hightube.db" with WAL mode and busy timeout enabled
+	DB, err = gorm.Open(sqlite.Open("hightube.db?_journal_mode=WAL&_busy_timeout=5000"), &gorm.Config{
 		Logger: newLogger,
 	})
 	if err != nil {
 		log.Fatalf("Failed to connect database: %v", err)
 	}
 
+	// Configure connection pool settings
+	sqlDB, err := DB.DB()
+	if err != nil {
+		log.Fatalf("Failed to get database instance: %v", err)
+	}
+	sqlDB.SetMaxOpenConns(10)
+	sqlDB.SetMaxIdleConns(5)
+	sqlDB.SetConnMaxLifetime(time.Hour)
+
 	// Auto-migrate the schema
 	err = DB.AutoMigrate(&model.User{}, &model.Room{})
 	if err != nil {
@@ -48,7 +57,7 @@ func InitDB() {
 
 	ensureAdminUser()
 
-	monitor.Infof("Database initialized successfully")
+	monitor.Infof("Database initialized successfully with WAL mode and connection pooling")
 }
 
 func ensureAdminUser() {

backend/internal/monitor/metrics.go

@@ -2,6 +2,7 @@ package monitor
 
 import (
 	"runtime"
+	"sync"
 	"sync/atomic"
 	"time"
 )
@@ -23,21 +24,32 @@ type Snapshot struct {
 	ErrorsTotal   uint64  `json:"errors_total"`
 }
 
-func IncrementRequestCount() {
-	atomic.AddUint64(&totalRequests, 1)
+var (
+	cachedSnapshot Snapshot
+	snapshotMutex  sync.RWMutex
+)
+
+func init() {
+	// Initialize the snapshot once on startup
+	updateSnapshot()
+
+	// Update the snapshot in the background every 2 seconds to avoid STW runtime.ReadMemStats in request threads
+	go func() {
+		ticker := time.NewTicker(2 * time.Second)
+		for range ticker.C {
+			updateSnapshot()
+		}
+	}()
 }
 
-func IncrementErrorCount() {
-	atomic.AddUint64(&totalErrors, 1)
-}
-
-func GetSnapshot() Snapshot {
+func updateSnapshot() {
 	var mem runtime.MemStats
 	runtime.ReadMemStats(&mem)
 
 	diskTotal, diskFree := getDiskSpaceGB()
 
-	return Snapshot{
+	snapshotMutex.Lock()
+	cachedSnapshot = Snapshot{
 		UptimeSeconds: int64(time.Since(startedAt).Seconds()),
 		Goroutines:    runtime.NumGoroutine(),
 		MemoryAllocMB: bytesToMB(mem.Alloc),
@@ -48,6 +60,28 @@ func GetSnapshot() Snapshot {
 		RequestsTotal: atomic.LoadUint64(&totalRequests),
 		ErrorsTotal:   atomic.LoadUint64(&totalErrors),
 	}
+	snapshotMutex.Unlock()
+}
+
+func IncrementRequestCount() {
+	atomic.AddUint64(&totalRequests, 1)
+}
+
+func IncrementErrorCount() {
+	atomic.AddUint64(&totalErrors, 1)
+}
+
+func GetSnapshot() Snapshot {
+	snapshotMutex.RLock()
+	defer snapshotMutex.RUnlock()
+
+	// Return the cached snapshot, overlaying volatile/cheap fields in real-time
+	s := cachedSnapshot
+	s.UptimeSeconds = int64(time.Since(startedAt).Seconds())
+	s.Goroutines = runtime.NumGoroutine()
+	s.RequestsTotal = atomic.LoadUint64(&totalRequests)
+	s.ErrorsTotal = atomic.LoadUint64(&totalErrors)
+	return s
 }
 
 func bytesToMB(v uint64) float64 {

backend/internal/stream/server.go

@@ -1,6 +1,7 @@
 package stream
 
 import (
+	"bufio"
 	"context"
 	"crypto/rand"
 	"encoding/hex"
@@ -15,6 +16,7 @@ import (
 	"time"
 
 	"github.com/gin-gonic/gin"
+	"github.com/nareix/joy4/av"
 	"github.com/nareix/joy4/av/avutil"
 	"github.com/nareix/joy4/av/pubsub"
 	"github.com/nareix/joy4/format"
@@ -82,6 +84,23 @@ func (w writeFlusher) Flush() error {
 	return nil
 }
 
+type bufferedWriteFlusher struct {
+	bufw        *bufio.Writer
+	httpFlusher http.Flusher
+}
+
+func (w *bufferedWriteFlusher) Write(p []byte) (n int, err error) {
+	return w.bufw.Write(p)
+}
+
+func (w *bufferedWriteFlusher) Flush() error {
+	if err := w.bufw.Flush(); err != nil {
+		return err
+	}
+	w.httpFlusher.Flush()
+	return nil
+}
+
 // NewRTMPServer creates and initializes a new media server
 func NewRTMPServer() *RTMPServer {
 	s := &RTMPServer{
@@ -235,13 +254,47 @@ func (s *RTMPServer) HandleHTTPFLV(c *gin.Context) {
 	c.Status(http.StatusOK)
 	flusher.Flush()
 
-	muxer := flv.NewMuxerWriteFlusher(writeFlusher{
+	// Coalesce the 3 internal write calls of WriteTag using a 4KB bufio.Writer
+	bufWriter := bufio.NewWriterSize(c.Writer, 4096)
+	bwf := &bufferedWriteFlusher{
+		bufw:        bufWriter,
 		httpFlusher: flusher,
-		Writer:      c.Writer,
-	})
+	}
+
+	muxer := flv.NewMuxerWriteFlusher(bwf)
 	cursor := q.Latest()
 
-	if err := avutil.CopyFile(muxer, cursor); err != nil && err != io.EOF {
+	// Write header first
+	streams, err := cursor.Streams()
+	if err != nil {
+		monitor.Errorf("HTTP-FLV failed to get cursor streams: %v", err)
+		return
+	}
+	if err = muxer.WriteHeader(streams); err != nil {
+		monitor.Errorf("HTTP-FLV failed to write header: %v", err)
+		return
+	}
+	if err = bwf.Flush(); err != nil {
+		return
+	}
+
+	// Read and write packet loop with per-packet flushing for low latency
+	for {
+		var pkt av.Packet
+		pkt, err = cursor.ReadPacket()
+		if err != nil {
+			break
+		}
+		if err = muxer.WritePacket(pkt); err != nil {
+			break
+		}
+		// Flush immediately so the frame is sent to the client (grouped write syscall)
+		if err = bwf.Flush(); err != nil {
+			break
+		}
+	}
+
+	if err != nil && err != io.EOF {
 		errStr := err.Error()
 		if strings.Contains(errStr, "broken pipe") || strings.Contains(errStr, "connection reset by peer") {
 			monitor.Infof("HTTP-FLV viewer disconnected: %s", streamPath)
@@ -299,10 +352,11 @@ func (s *RTMPServer) startVariantTranscoders(roomID string) {
 			"ffmpeg",
 			"-nostdin",
 			"-loglevel", "error",
+			"-fflags", "nobuffer",
 			"-i", inputURL,
 			"-vf", "scale="+profile.scale+":force_original_aspect_ratio=decrease",
 			"-c:v", "libx264",
-			"-preset", "veryfast",
+			"-preset", "ultrafast",
 			"-tune", "zerolatency",
 			"-g", "48",
 			"-keyint_min", "48",

frontend/web/flv_player.html

@@ -81,6 +81,7 @@
         isLive: true,
       }, {
         enableWorker: false,
+        enableStashBuffer: false,
         stashInitialSize: 128,
       });
 
@@ -88,6 +89,24 @@
       player.load();
       player.play().catch(() => {});
 
+      // Live latency auto-catchup logic
+      video.addEventListener('timeupdate', function() {
+        if (video.buffered.length > 0) {
+          const end = video.buffered.end(video.buffered.length - 1);
+          const diff = end - video.currentTime;
+          if (diff > 5) {
+            // If way behind, jump directly close to the live edge
+            video.currentTime = end - 1.0;
+          } else if (diff > 1.5) {
+            // Speed up slightly to catch up
+            video.playbackRate = 1.15;
+          } else {
+            // Reset to normal speed
+            video.playbackRate = 1.0;
+          }
+        }
+      });
+
       player.on(flvjs.Events.ERROR, function(errorType, detail, info) {
         const parts = ['Live stream failed to load.'];
         if (errorType) parts.push('type=' + errorType);