diff --git a/internal/repository/strm_repository.go b/internal/repository/strm_repository.go
index 6e25ad8..55a111f 100644
--- a/internal/repository/strm_repository.go
+++ b/internal/repository/strm_repository.go
@@ -3,6 +3,7 @@ package repository
 import (
 	"context"
 	"errors"
+	"sync"
 	"time"
 
 	"gorm.io/gorm"
@@ -10,13 +11,17 @@ import (
 	"github.com/ShukeBta/MMTL/internal/model"
 )
 
+var strmClaimMu sync.Mutex
+
 // ─── StrmAccount ───────────────────────────────────────────────────────────────
 
 // StrmAccountRepository persists model.StrmAccount.
 type StrmAccountRepository struct{ db *gorm.DB }
 
 func (r *StrmAccountRepository) Create(ctx context.Context, a *model.StrmAccount) error {
-	return r.db.WithContext(ctx).Create(a).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Create(a).Error
+	})
 }
 
 func (r *StrmAccountRepository) FindByID(ctx context.Context, id string) (*model.StrmAccount, error) {
@@ -38,20 +43,24 @@ func (r *StrmAccountRepository) List(ctx context.Context) ([]model.StrmAccount,
 }
 
 func (r *StrmAccountRepository) Update(ctx context.Context, a *model.StrmAccount) error {
-	return r.db.WithContext(ctx).Model(&model.StrmAccount{}).Where("id = ?", a.ID).Updates(map[string]any{
-		"name":             a.Name,
-		"provider":         a.Provider,
-		"config":           a.Config,
-		"enabled":          a.Enabled,
-		"last_test_at":     a.LastTestAt,
-		"last_test_result": a.LastTestResult,
-		"last_test_ok":     a.LastTestOK,
-		"updated_at":       time.Now(),
-	}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Model(&model.StrmAccount{}).Where("id = ?", a.ID).Updates(map[string]any{
+			"name":             a.Name,
+			"provider":         a.Provider,
+			"config":           a.Config,
+			"enabled":          a.Enabled,
+			"last_test_at":     a.LastTestAt,
+			"last_test_result": a.LastTestResult,
+			"last_test_ok":     a.LastTestOK,
+			"updated_at":       time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmAccountRepository) Delete(ctx context.Context, id string) error {
-	return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmAccount{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmAccount{}).Error
+	})
 }
 
 // ─── StrmSyncPath ──────────────────────────────────────────────────────────────
@@ -60,7 +69,9 @@ func (r *StrmAccountRepository) Delete(ctx context.Context, id string) error {
 type StrmSyncPathRepository struct{ db *gorm.DB }
 
 func (r *StrmSyncPathRepository) Create(ctx context.Context, p *model.StrmSyncPath) error {
-	return r.db.WithContext(ctx).Create(p).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Create(p).Error
+	})
 }
 
 func (r *StrmSyncPathRepository) FindByID(ctx context.Context, id string) (*model.StrmSyncPath, error) {
@@ -82,34 +93,38 @@ func (r *StrmSyncPathRepository) List(ctx context.Context) ([]model.StrmSyncPath
 }
 
 func (r *StrmSyncPathRepository) Update(ctx context.Context, p *model.StrmSyncPath) error {
-	return r.db.WithContext(ctx).Model(&model.StrmSyncPath{}).Where("id = ?", p.ID).Updates(map[string]any{
-		"name":              p.Name,
-		"account_id":        p.AccountID,
-		"provider":          p.Provider,
-		"remote_path":       p.RemotePath,
-		"local_path":        p.LocalPath,
-		"strm_base_url":     p.StrmBaseURL,
-		"video_ext":         p.VideoExt,
-		"meta_ext":          p.MetaExt,
-		"exclude_name":      p.ExcludeName,
-		"min_video_size_mb": p.MinVideoSizeMB,
-		"add_path":          p.AddPath,
-		"download_meta":     p.DownloadMeta,
-		"upload_meta":       p.UploadMeta,
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Model(&model.StrmSyncPath{}).Where("id = ?", p.ID).Updates(map[string]any{
+			"name":              p.Name,
+			"account_id":        p.AccountID,
+			"provider":          p.Provider,
+			"remote_path":       p.RemotePath,
+			"local_path":        p.LocalPath,
+			"strm_base_url":     p.StrmBaseURL,
+			"video_ext":         p.VideoExt,
+			"meta_ext":          p.MetaExt,
+			"exclude_name":      p.ExcludeName,
+			"min_video_size_mb": p.MinVideoSizeMB,
+			"add_path":          p.AddPath,
+			"download_meta":     p.DownloadMeta,
+			"upload_meta":       p.UploadMeta,
 			"delete_dir":        p.DeleteDir,
 			"cron":              p.Cron,
 			"enable_cron":       p.EnableCron,
 			"sync_mode":         p.SyncMode,
 			"enabled":           p.Enabled,
 			"last_sync_at":      p.LastSyncAt,
-		"last_sync_status":  p.LastSyncStatus,
-		"last_sync_message": p.LastSyncMessage,
-		"updated_at":        time.Now(),
-	}).Error
+			"last_sync_status":  p.LastSyncStatus,
+			"last_sync_message": p.LastSyncMessage,
+			"updated_at":        time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmSyncPathRepository) Delete(ctx context.Context, id string) error {
-	return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmSyncPath{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmSyncPath{}).Error
+	})
 }
 
 // ─── StrmSyncRecord ────────────────────────────────────────────────────────────
@@ -118,24 +133,28 @@ func (r *StrmSyncPathRepository) Delete(ctx context.Context, id string) error {
 type StrmSyncRecordRepository struct{ db *gorm.DB }
 
 func (r *StrmSyncRecordRepository) Create(ctx context.Context, rec *model.StrmSyncRecord) error {
-	return r.db.WithContext(ctx).Create(rec).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Create(rec).Error
+	})
 }
 
 func (r *StrmSyncRecordRepository) Update(ctx context.Context, rec *model.StrmSyncRecord) error {
-	return r.db.WithContext(ctx).Model(&model.StrmSyncRecord{}).Where("id = ?", rec.ID).Updates(map[string]any{
-		"sync_type":   rec.SyncType,
-		"status":      rec.Status,
-		"total":       rec.Total,
-		"new_strm":    rec.NewStrm,
-		"new_meta":    rec.NewMeta,
-		"uploaded":    rec.Uploaded,
-		"pruned":      rec.Pruned,
-		"skipped":     rec.Skipped,
-		"message":     rec.Message,
-		"started_at":  rec.StartedAt,
-		"finished_at": rec.FinishedAt,
-		"updated_at":  time.Now(),
-	}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Model(&model.StrmSyncRecord{}).Where("id = ?", rec.ID).Updates(map[string]any{
+			"sync_type":   rec.SyncType,
+			"status":      rec.Status,
+			"total":       rec.Total,
+			"new_strm":    rec.NewStrm,
+			"new_meta":    rec.NewMeta,
+			"uploaded":    rec.Uploaded,
+			"pruned":      rec.Pruned,
+			"skipped":     rec.Skipped,
+			"message":     rec.Message,
+			"started_at":  rec.StartedAt,
+			"finished_at": rec.FinishedAt,
+			"updated_at":  time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmSyncRecordRepository) List(ctx context.Context, syncPathID string, limit int) ([]model.StrmSyncRecord, error) {
@@ -157,7 +176,21 @@ func (r *StrmSyncRecordRepository) List(ctx context.Context, syncPathID string,
 type StrmDownloadTaskRepository struct{ db *gorm.DB }
 
 func (r *StrmDownloadTaskRepository) Create(ctx context.Context, t *model.StrmDownloadTask) error {
-	return r.db.WithContext(ctx).Create(t).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Create(t).Error
+	})
+}
+
+func (r *StrmDownloadTaskRepository) CreateInBatches(ctx context.Context, tasks []*model.StrmDownloadTask, batchSize int) error {
+	if len(tasks) == 0 {
+		return nil
+	}
+	if batchSize <= 0 {
+		batchSize = 100
+	}
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).CreateInBatches(tasks, batchSize).Error
+	})
 }
 
 func (r *StrmDownloadTaskRepository) FindByID(ctx context.Context, id string) (*model.StrmDownloadTask, error) {
@@ -207,24 +240,29 @@ func (r *StrmDownloadTaskRepository) CountByStatus(ctx context.Context) (map[str
 // ClaimPendingDownload picks the oldest pending task and marks it running.
 // Returns (nil, nil) when the queue is empty.
 func (r *StrmDownloadTaskRepository) ClaimPendingDownload(ctx context.Context, limit int) ([]model.StrmDownloadTask, error) {
+	strmClaimMu.Lock()
+	defer strmClaimMu.Unlock()
+
 	var rows []model.StrmDownloadTask
-	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
-		if err := tx.Where("status = ? AND (next_try_at IS NULL OR next_try_at <= ?)", model.StrmTaskPending, time.Now()).
-			Order("created_at asc").Limit(limit).Find(&rows).Error; err != nil {
-			return err
-		}
-		if len(rows) == 0 {
-			return nil
-		}
-		ids := make([]string, 0, len(rows))
-		now := time.Now()
-		for i := range rows {
-			ids = append(ids, rows[i].ID)
-			rows[i].Status = model.StrmTaskRunning
-			rows[i].StartedAt = &now
-		}
-		return tx.Model(&model.StrmDownloadTask{}).Where("id IN ?", ids).
-			Updates(map[string]any{"status": model.StrmTaskRunning, "started_at": now}).Error
+	err := withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+			if err := tx.Where("status = ? AND (next_try_at IS NULL OR next_try_at <= ?)", model.StrmTaskPending, time.Now()).
+				Order("created_at asc").Limit(limit).Find(&rows).Error; err != nil {
+				return err
+			}
+			if len(rows) == 0 {
+				return nil
+			}
+			ids := make([]string, 0, len(rows))
+			now := time.Now()
+			for i := range rows {
+				ids = append(ids, rows[i].ID)
+				rows[i].Status = model.StrmTaskRunning
+				rows[i].StartedAt = &now
+			}
+			return tx.Model(&model.StrmDownloadTask{}).Where("id IN ?", ids).
+				Updates(map[string]any{"status": model.StrmTaskRunning, "started_at": now}).Error
+		})
 	})
 	if err != nil {
 		return nil, err
@@ -233,62 +271,86 @@ func (r *StrmDownloadTaskRepository) ClaimPendingDownload(ctx context.Context, l
 }
 
 func (r *StrmDownloadTaskRepository) Update(ctx context.Context, t *model.StrmDownloadTask) error {
-	return r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).Where("id = ?", t.ID).Updates(map[string]any{
-		"status":      t.Status,
-		"error":       t.Error,
-		"retry_count": t.RetryCount,
-		"next_try_at": t.NextTryAt,
-		"started_at":  t.StartedAt,
-		"finished_at": t.FinishedAt,
-		"updated_at":  time.Now(),
-	}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).Where("id = ?", t.ID).Updates(map[string]any{
+			"status":      t.Status,
+			"error":       t.Error,
+			"retry_count": t.RetryCount,
+			"next_try_at": t.NextTryAt,
+			"started_at":  t.StartedAt,
+			"finished_at": t.FinishedAt,
+			"updated_at":  time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmDownloadTaskRepository) Delete(ctx context.Context, id string) error {
-	return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmDownloadTask{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmDownloadTask{}).Error
+	})
 }
 
 // ClearDone 清空全部已完成下载任务。
 func (r *StrmDownloadTaskRepository) ClearDone(ctx context.Context) (int64, error) {
-	res := r.db.WithContext(ctx).Where("status = ?", model.StrmTaskDone).Delete(&model.StrmDownloadTask{})
-	return res.RowsAffected, res.Error
+	var count int64
+	err := withSQLiteBusyRetry(ctx, func() error {
+		res := r.db.WithContext(ctx).Where("status = ?", model.StrmTaskDone).Delete(&model.StrmDownloadTask{})
+		count = res.RowsAffected
+		return res.Error
+	})
+	return count, err
 }
 
 // ClearFinished 清空全部已完成与失败下载任务。
 func (r *StrmDownloadTaskRepository) ClearFinished(ctx context.Context) (int64, error) {
-	res := r.db.WithContext(ctx).Where("status IN ?", []string{model.StrmTaskDone, model.StrmTaskFailed}).
-		Delete(&model.StrmDownloadTask{})
-	return res.RowsAffected, res.Error
+	var count int64
+	err := withSQLiteBusyRetry(ctx, func() error {
+		res := r.db.WithContext(ctx).Where("status IN ?", []string{model.StrmTaskDone, model.StrmTaskFailed}).
+			Delete(&model.StrmDownloadTask{})
+		count = res.RowsAffected
+		return res.Error
+	})
+	return count, err
 }
 
 // RetryAllFailed 把所有失败任务重置回待处理，清空错误与重试计数。
 func (r *StrmDownloadTaskRepository) RetryAllFailed(ctx context.Context) (int64, error) {
-	res := r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).
-		Where("status = ?", model.StrmTaskFailed).
-		Updates(map[string]any{
-			"status":      model.StrmTaskPending,
-			"error":       "",
-			"retry_count": 0,
-			"next_try_at": nil,
-			"started_at":  nil,
-			"finished_at": nil,
-			"updated_at":  time.Now(),
-		})
-	return res.RowsAffected, res.Error
+	var count int64
+	err := withSQLiteBusyRetry(ctx, func() error {
+		res := r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).
+			Where("status = ?", model.StrmTaskFailed).
+			Updates(map[string]any{
+				"status":      model.StrmTaskPending,
+				"error":       "",
+				"retry_count": 0,
+				"next_try_at": nil,
+				"started_at":  nil,
+				"finished_at": nil,
+				"updated_at":  time.Now(),
+			})
+		count = res.RowsAffected
+		return res.Error
+	})
+	return count, err
 }
 
 // CancelPending 批量取消所有排队中的任务。
 func (r *StrmDownloadTaskRepository) CancelPending(ctx context.Context) (int64, error) {
 	now := time.Now()
-	res := r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).
-		Where("status = ?", model.StrmTaskPending).
-		Updates(map[string]any{
-			"status":      model.StrmTaskCanceled,
-			"error":       "已批量取消",
-			"finished_at": now,
-			"updated_at":  now,
-		})
-	return res.RowsAffected, res.Error
+	var count int64
+	err := withSQLiteBusyRetry(ctx, func() error {
+		res := r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).
+			Where("status = ?", model.StrmTaskPending).
+			Updates(map[string]any{
+				"status":      model.StrmTaskCanceled,
+				"error":       "已批量取消",
+				"finished_at": now,
+				"updated_at":  now,
+			})
+		count = res.RowsAffected
+		return res.Error
+	})
+	return count, err
 }
 
 // CountActive 统计某同步目录下目标仍在排队/进行的任务数（用于去重）。
@@ -301,10 +363,28 @@ func (r *StrmDownloadTaskRepository) CountActive(ctx context.Context, syncPathID
 	return count
 }
 
+// GetActiveLocalPathMap 一次性获取某同步目录下正在排队或执行中的 local_path 集合，供同步时 O(1) 内存去重。
+func (r *StrmDownloadTaskRepository) GetActiveLocalPathMap(ctx context.Context, syncPathID string) (map[string]bool, error) {
+	var paths []string
+	err := r.db.WithContext(ctx).Model(&model.StrmDownloadTask{}).
+		Where("sync_path_id = ? AND status IN ?", syncPathID, []string{model.StrmTaskPending, model.StrmTaskRunning}).
+		Pluck("local_path", &paths).Error
+	if err != nil {
+		return nil, err
+	}
+	out := make(map[string]bool, len(paths))
+	for _, p := range paths {
+		out[p] = true
+	}
+	return out, nil
+}
+
 func (r *StrmDownloadTaskRepository) DeleteFinishedOlderThan(ctx context.Context, before time.Time) error {
-	return r.db.WithContext(ctx).Where("status IN ? AND finished_at < ?",
-		[]string{model.StrmTaskDone, model.StrmTaskFailed, model.StrmTaskCanceled}, before).
-		Delete(&model.StrmDownloadTask{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("status IN ? AND finished_at < ?",
+			[]string{model.StrmTaskDone, model.StrmTaskFailed, model.StrmTaskCanceled}, before).
+			Delete(&model.StrmDownloadTask{}).Error
+	})
 }
 
 // ─── StrmUploadTask ────────────────────────────────────────────────────────────
@@ -313,7 +393,21 @@ func (r *StrmDownloadTaskRepository) DeleteFinishedOlderThan(ctx context.Context
 type StrmUploadTaskRepository struct{ db *gorm.DB }
 
 func (r *StrmUploadTaskRepository) Create(ctx context.Context, t *model.StrmUploadTask) error {
-	return r.db.WithContext(ctx).Create(t).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Create(t).Error
+	})
+}
+
+func (r *StrmUploadTaskRepository) CreateInBatches(ctx context.Context, tasks []*model.StrmUploadTask, batchSize int) error {
+	if len(tasks) == 0 {
+		return nil
+	}
+	if batchSize <= 0 {
+		batchSize = 100
+	}
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).CreateInBatches(tasks, batchSize).Error
+	})
 }
 
 func (r *StrmUploadTaskRepository) FindByID(ctx context.Context, id string) (*model.StrmUploadTask, error) {
@@ -382,24 +476,29 @@ func (r *StrmUploadTaskRepository) CountByStatus(ctx context.Context) (map[strin
 // ClaimPendingUpload picks the oldest pending task and marks it running.
 // Returns (nil, nil) when the queue is empty.
 func (r *StrmUploadTaskRepository) ClaimPendingUpload(ctx context.Context, limit int) ([]model.StrmUploadTask, error) {
+	strmClaimMu.Lock()
+	defer strmClaimMu.Unlock()
+
 	var rows []model.StrmUploadTask
-	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
-		if err := tx.Where("status = ? AND (next_try_at IS NULL OR next_try_at <= ?)", model.StrmTaskPending, time.Now()).
-			Order("created_at asc").Limit(limit).Find(&rows).Error; err != nil {
-			return err
-		}
-		if len(rows) == 0 {
-			return nil
-		}
-		ids := make([]string, 0, len(rows))
-		now := time.Now()
-		for i := range rows {
-			ids = append(ids, rows[i].ID)
-			rows[i].Status = model.StrmTaskRunning
-			rows[i].StartedAt = &now
-		}
-		return tx.Model(&model.StrmUploadTask{}).Where("id IN ?", ids).
-			Updates(map[string]any{"status": model.StrmTaskRunning, "started_at": now}).Error
+	err := withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+			if err := tx.Where("status = ? AND (next_try_at IS NULL OR next_try_at <= ?)", model.StrmTaskPending, time.Now()).
+				Order("created_at asc").Limit(limit).Find(&rows).Error; err != nil {
+				return err
+			}
+			if len(rows) == 0 {
+				return nil
+			}
+			ids := make([]string, 0, len(rows))
+			now := time.Now()
+			for i := range rows {
+				ids = append(ids, rows[i].ID)
+				rows[i].Status = model.StrmTaskRunning
+				rows[i].StartedAt = &now
+			}
+			return tx.Model(&model.StrmUploadTask{}).Where("id IN ?", ids).
+				Updates(map[string]any{"status": model.StrmTaskRunning, "started_at": now}).Error
+		})
 	})
 	if err != nil {
 		return nil, err
@@ -408,19 +507,23 @@ func (r *StrmUploadTaskRepository) ClaimPendingUpload(ctx context.Context, limit
 }
 
 func (r *StrmUploadTaskRepository) Update(ctx context.Context, t *model.StrmUploadTask) error {
-	return r.db.WithContext(ctx).Model(&model.StrmUploadTask{}).Where("id = ?", t.ID).Updates(map[string]any{
-		"status":      t.Status,
-		"error":       t.Error,
-		"retry_count": t.RetryCount,
-		"next_try_at": t.NextTryAt,
-		"started_at":  t.StartedAt,
-		"finished_at": t.FinishedAt,
-		"updated_at":  time.Now(),
-	}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Model(&model.StrmUploadTask{}).Where("id = ?", t.ID).Updates(map[string]any{
+			"status":      t.Status,
+			"error":       t.Error,
+			"retry_count": t.RetryCount,
+			"next_try_at": t.NextTryAt,
+			"started_at":  t.StartedAt,
+			"finished_at": t.FinishedAt,
+			"updated_at":  time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmUploadTaskRepository) Delete(ctx context.Context, id string) error {
-	return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmUploadTask{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("id = ?", id).Delete(&model.StrmUploadTask{}).Error
+	})
 }
 
 // CountActive 统计某同步目录下目标仍在排队/进行的任务数（用于去重）。
@@ -433,10 +536,28 @@ func (r *StrmUploadTaskRepository) CountActive(ctx context.Context, syncPathID,
 	return count
 }
 
+// GetActiveLocalPathMap 一次性获取某同步目录下正在排队或执行中的 local_path 集合，供同步时 O(1) 内存去重。
+func (r *StrmUploadTaskRepository) GetActiveLocalPathMap(ctx context.Context, syncPathID string) (map[string]bool, error) {
+	var paths []string
+	err := r.db.WithContext(ctx).Model(&model.StrmUploadTask{}).
+		Where("sync_path_id = ? AND status IN ?", syncPathID, []string{model.StrmTaskPending, model.StrmTaskRunning}).
+		Pluck("local_path", &paths).Error
+	if err != nil {
+		return nil, err
+	}
+	out := make(map[string]bool, len(paths))
+	for _, p := range paths {
+		out[p] = true
+	}
+	return out, nil
+}
+
 func (r *StrmUploadTaskRepository) DeleteFinishedOlderThan(ctx context.Context, before time.Time) error {
-	return r.db.WithContext(ctx).Where("status IN ? AND finished_at < ?",
-		[]string{model.StrmTaskDone, model.StrmTaskFailed, model.StrmTaskCanceled}, before).
-		Delete(&model.StrmUploadTask{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("status IN ? AND finished_at < ?",
+			[]string{model.StrmTaskDone, model.StrmTaskFailed, model.StrmTaskCanceled}, before).
+			Delete(&model.StrmUploadTask{}).Error
+	})
 }
 
 // ─── StrmDirCache ─────────────────────────────────────────────────────────────
@@ -451,26 +572,31 @@ func (r *StrmDirCacheRepository) ListBySyncPathID(ctx context.Context, syncPathI
 }
 
 func (r *StrmDirCacheRepository) Set(ctx context.Context, syncPathID, dirID, path string) error {
-	var row model.StrmDirCache
-	err := r.db.WithContext(ctx).Where("sync_path_id = ? AND dir_id = ?", syncPathID, dirID).First(&row).Error
-	if errors.Is(err, gorm.ErrRecordNotFound) {
-		row = model.StrmDirCache{
-			SyncPathID: syncPathID,
-			DirID:      dirID,
-			Path:       path,
+	return withSQLiteBusyRetry(ctx, func() error {
+		var row model.StrmDirCache
+		err := r.db.WithContext(ctx).Where("sync_path_id = ? AND dir_id = ?", syncPathID, dirID).First(&row).Error
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			row = model.StrmDirCache{
+				SyncPathID: syncPathID,
+				DirID:      dirID,
+				Path:       path,
+			}
+			return r.db.WithContext(ctx).Create(&row).Error
 		}
-		return r.db.WithContext(ctx).Create(&row).Error
-	}
-	if err != nil {
-		return err
-	}
-	return r.db.WithContext(ctx).Model(&model.StrmDirCache{}).Where("id = ?", row.ID).Updates(map[string]any{
-		"path":       path,
-		"updated_at": time.Now(),
-	}).Error
+		if err != nil {
+			return err
+		}
+		return r.db.WithContext(ctx).Model(&model.StrmDirCache{}).Where("id = ?", row.ID).Updates(map[string]any{
+			"path":       path,
+			"updated_at": time.Now(),
+		}).Error
+	})
 }
 
 func (r *StrmDirCacheRepository) DeleteBySyncPathID(ctx context.Context, syncPathID string) error {
-	return r.db.WithContext(ctx).Where("sync_path_id = ?", syncPathID).Delete(&model.StrmDirCache{}).Error
+	return withSQLiteBusyRetry(ctx, func() error {
+		return r.db.WithContext(ctx).Where("sync_path_id = ?", syncPathID).Delete(&model.StrmDirCache{}).Error
+	})
 }
 
+
diff --git a/internal/service/strm_sync.go b/internal/service/strm_sync.go
index 7ca89d3..4c34ebe 100644
--- a/internal/service/strm_sync.go
+++ b/internal/service/strm_sync.go
@@ -34,12 +34,17 @@ type strmSyncState struct {
 	rec      *model.StrmSyncRecord
 	syncType string
 
-	mu         sync.Mutex
-	processed  int              // 已处理文件计数（用于定期落库进度）
-	seenVideo  map[string]bool  // "v:"+去掉扩展名的相对路径 → 远端存在该视频
-	seenMeta   map[string]bool  // "m:"+相对路径 → 远端存在该元数据
-	remoteMeta map[string]int64 // 远端元数据大小（上传比对用）
-	dirCache   sync.Map         // dirID (string) -> relativePath (string)
+	mu                  sync.Mutex
+	processed           int              // 已处理文件计数（用于定期落库进度）
+	lastProgressFlush   time.Time        // 上次进度落库时间
+	seenVideo           map[string]bool  // "v:"+去掉扩展名的相对路径 → 远端存在该视频
+	seenMeta            map[string]bool  // "m:"+相对路径 → 远端存在该元数据
+	remoteMeta          map[string]int64 // 远端元数据大小（上传比对用）
+	activeDownloadPaths map[string]bool  // 本地已在排队/进行的下载任务路径（内存去重）
+	activeUploadPaths   map[string]bool  // 本地已在排队/进行的上传任务路径（内存去重）
+	pendingDownloads    []*model.StrmDownloadTask
+	pendingUploads      []*model.StrmUploadTask
+	dirCache            sync.Map // dirID (string) -> relativePath (string)
 }
 
 // StartSync 启动一次同步（异步执行，同一目录同时只允许一个任务）。
@@ -227,6 +232,21 @@ func (st *strmSyncState) run() error {
 	if err := ensureLocalDir(st.p.LocalPath); err != nil {
 		return fmt.Errorf("创建输出目录失败：%w", err)
 	}
+	if st.cfg.DownloadMeta {
+		if active, err := st.s.repo.StrmDownload.GetActiveLocalPathMap(st.ctx, st.p.ID); err == nil {
+			st.activeDownloadPaths = active
+		} else {
+			st.activeDownloadPaths = map[string]bool{}
+		}
+	}
+	if st.cfg.UploadMeta {
+		if active, err := st.s.repo.StrmUpload.GetActiveLocalPathMap(st.ctx, st.p.ID); err == nil {
+			st.activeUploadPaths = active
+		} else {
+			st.activeUploadPaths = map[string]bool{}
+		}
+	}
+
 	if st.provider != nil {
 		if open115, ok := st.provider.(cloud.OpenAPI115Provider); ok && st.p.Provider == model.StrmProvider115 {
 			if err := st.walk115Flat(open115.OpenClient()); err != nil {
@@ -242,11 +262,13 @@ func (st *strmSyncState) run() error {
 			return err
 		}
 	}
+	st.flushPendingDownloads()
 	st.flushProgress()
 	if st.cfg.UploadMeta && st.provider != nil && st.p.Provider != model.StrmProvider115 {
 		if err := st.scanLocalMetaForUpload(); err != nil {
 			return err
 		}
+		st.flushPendingUploads()
 	}
 	if err := st.pruneLocal(); err != nil {
 		return err
@@ -265,6 +287,7 @@ const strmScanWorkers = 8
 // 多个 worker 并行执行 List（受全局 115 令牌桶限流约束），子目录动态
 // 入队；任一目录失败则取消其余 worker 并返回错误（与旧串行版语义一致）。
 func (st *strmSyncState) walkRemote() error {
+	defer st.flushPendingDownloads()
 	root := strings.TrimSpace(st.p.RemotePath)
 	if root == "" {
 		root = "/"
@@ -403,6 +426,7 @@ func (st *strmSyncState) isMetaExt(ext string) bool {
 // walk115Flat 使用 115 开放平台扁平化分页批量拉取机制与目录拓扑缓存（参考 QMediaSync）。
 // 极大地降低 API 请求次数并支持毫秒级/秒级增量同步。
 func (st *strmSyncState) walk115Flat(open115 *cloud115.OpenClient) error {
+	defer st.flushPendingDownloads()
 	ctx := st.ctx
 	rootCID := strings.TrimSpace(st.p.RemotePath)
 	if rootCID == "" {
@@ -738,6 +762,36 @@ func (st *strmSyncState) recordRemoteMeta(entry cloud.FileEntry, rel string) {
 	st.mu.Unlock()
 }
 
+func (st *strmSyncState) flushPendingDownloads() {
+	st.mu.Lock()
+	if len(st.pendingDownloads) == 0 {
+		st.mu.Unlock()
+		return
+	}
+	batch := st.pendingDownloads
+	st.pendingDownloads = nil
+	st.mu.Unlock()
+
+	if err := st.s.repo.StrmDownload.CreateInBatches(st.ctx, batch, 100); err != nil {
+		st.s.log.Warn("batch enqueue strm download tasks failed", zap.Error(err))
+	}
+}
+
+func (st *strmSyncState) flushPendingUploads() {
+	st.mu.Lock()
+	if len(st.pendingUploads) == 0 {
+		st.mu.Unlock()
+		return
+	}
+	batch := st.pendingUploads
+	st.pendingUploads = nil
+	st.mu.Unlock()
+
+	if err := st.s.repo.StrmUpload.CreateInBatches(st.ctx, batch, 100); err != nil {
+		st.s.log.Warn("batch enqueue strm upload tasks failed", zap.Error(err))
+	}
+}
+
 // handleMeta 元数据入下载队列（本地已存在且大小一致则跳过）。
 func (st *strmSyncState) handleMeta(entry cloud.FileEntry, rel, ext string) {
 	st.recordRemoteMeta(entry, rel)
@@ -750,10 +804,22 @@ func (st *strmSyncState) handleMeta(entry cloud.FileEntry, rel, ext string) {
 		st.touchProgress()
 		return
 	}
-	if st.taskExists("download", st.p.ID, target) {
+	st.mu.Lock()
+	if st.activeDownloadPaths == nil {
+		if active, err := st.s.repo.StrmDownload.GetActiveLocalPathMap(st.ctx, st.p.ID); err == nil {
+			st.activeDownloadPaths = active
+		} else {
+			st.activeDownloadPaths = map[string]bool{}
+		}
+	}
+	if st.activeDownloadPaths[target] {
+		st.mu.Unlock()
 		st.touchProgress()
 		return
 	}
+	st.activeDownloadPaths[target] = true
+	st.mu.Unlock()
+
 	task := &model.StrmDownloadTask{
 		SyncPathID: st.p.ID,
 		AccountID:  st.p.AccountID,
@@ -772,13 +838,16 @@ func (st *strmSyncState) handleMeta(entry cloud.FileEntry, rel, ext string) {
 	if st.p.Provider != model.StrmProvider115 {
 		task.RemoteRef = entry.ID
 	}
-	if err := st.s.repo.StrmDownload.Create(st.ctx, task); err != nil {
-		st.s.log.Warn("enqueue strm download task failed", zap.Error(err))
-		return
-	}
+
 	st.mu.Lock()
+	st.pendingDownloads = append(st.pendingDownloads, task)
+	shouldFlush := len(st.pendingDownloads) >= 100
 	st.rec.NewMeta++
 	st.mu.Unlock()
+
+	if shouldFlush {
+		st.flushPendingDownloads()
+	}
 	st.touchProgress()
 }
 
@@ -872,67 +941,84 @@ func (st *strmSyncState) walkLocalSource() error {
 	})
 }
 
-// scanLocalMetaForUpload 扫描本地元数据，与远端比对后入上传队列。
-func (st *strmSyncState) scanLocalMetaForUpload() error {
-	localRoot := filepath.Clean(st.p.LocalPath)
-	return filepath.WalkDir(localRoot, func(path string, d os.DirEntry, err error) error {
-		if err != nil {
+	// scanLocalMetaForUpload 扫描本地元数据，与远端比对后入上传队列。
+	func (st *strmSyncState) scanLocalMetaForUpload() error {
+		defer st.flushPendingUploads()
+		if st.activeUploadPaths == nil {
+			if active, err := st.s.repo.StrmUpload.GetActiveLocalPathMap(st.ctx, st.p.ID); err == nil {
+				st.activeUploadPaths = active
+			} else {
+				st.activeUploadPaths = map[string]bool{}
+			}
+		}
+		localRoot := filepath.Clean(st.p.LocalPath)
+		return filepath.WalkDir(localRoot, func(path string, d os.DirEntry, err error) error {
+			if err != nil {
+				return nil
+			}
+			if path == localRoot {
+				return nil
+			}
+			select {
+			case <-st.ctx.Done():
+				return st.ctx.Err()
+			default:
+			}
+			if d.IsDir() {
+				return nil
+			}
+			rel, err := filepath.Rel(localRoot, path)
+			if err != nil {
+				return nil
+			}
+			rel = filepath.ToSlash(rel)
+			ext := strings.ToLower(filepath.Ext(rel))
+			if !st.isMetaExt(ext) {
+				return nil
+			}
+			info, err := d.Info()
+			if err != nil {
+				return nil
+			}
+			st.mu.Lock()
+			_, exists := st.remoteMeta["m:"+rel]
+			st.mu.Unlock()
+			if exists {
+				// 网盘端已存在该元数据文件，跳过上传
+				return nil
+			}
+			st.mu.Lock()
+			if st.activeUploadPaths != nil && st.activeUploadPaths[path] {
+				st.mu.Unlock()
+				return nil
+			}
+			if st.activeUploadPaths != nil {
+				st.activeUploadPaths[path] = true
+			}
+			st.mu.Unlock()
+
+			task := &model.StrmUploadTask{
+				SyncPathID: st.p.ID,
+				AccountID:  st.p.AccountID,
+				Provider:   st.p.Provider,
+				FileName:   filepath.Base(rel),
+				LocalPath:  path,
+				RemotePath: st.remoteUploadPath(rel),
+				Size:       info.Size(),
+				Status:     model.StrmTaskPending,
+			}
+			st.mu.Lock()
+			st.pendingUploads = append(st.pendingUploads, task)
+			shouldFlush := len(st.pendingUploads) >= 100
+			st.rec.Uploaded++
+			st.mu.Unlock()
+
+			if shouldFlush {
+				st.flushPendingUploads()
+			}
 			return nil
-		}
-		if path == localRoot {
-			return nil
-		}
-		select {
-		case <-st.ctx.Done():
-			return st.ctx.Err()
-		default:
-		}
-		if d.IsDir() {
-			return nil
-		}
-		rel, err := filepath.Rel(localRoot, path)
-		if err != nil {
-			return nil
-		}
-		rel = filepath.ToSlash(rel)
-		ext := strings.ToLower(filepath.Ext(rel))
-		if !st.isMetaExt(ext) {
-			return nil
-		}
-		info, err := d.Info()
-		if err != nil {
-			return nil
-		}
-		st.mu.Lock()
-		_, exists := st.remoteMeta["m:"+rel]
-		st.mu.Unlock()
-		if exists {
-			// 网盘端已存在该元数据文件，跳过上传
-			return nil
-		}
-		if st.taskExists("upload", st.p.ID, path) {
-			return nil
-		}
-		task := &model.StrmUploadTask{
-			SyncPathID: st.p.ID,
-			AccountID:  st.p.AccountID,
-			Provider:   st.p.Provider,
-			FileName:   filepath.Base(rel),
-			LocalPath:  path,
-			RemotePath: st.remoteUploadPath(rel),
-			Size:       info.Size(),
-			Status:     model.StrmTaskPending,
-		}
-		if err := st.s.repo.StrmUpload.Create(st.ctx, task); err != nil {
-			st.s.log.Warn("enqueue strm upload task failed", zap.Error(err))
-			return nil
-		}
-		st.mu.Lock()
-		st.rec.Uploaded++
-		st.mu.Unlock()
-		return nil
-	})
-}
+		})
+	}
 
 // remoteUploadPath 远端元数据目标路径 = 同步目录远端根 + 相对路径。
 func (st *strmSyncState) remoteUploadPath(rel string) string {
@@ -1018,12 +1104,16 @@ func (st *strmSyncState) pruneLocal() error {
 	return nil
 }
 
-// touchProgress 每处理若干个文件落库一次进度。
+// touchProgress 进度计数并限流防抖落库（避免高频写 SQLite 导致锁竞争）。
 func (st *strmSyncState) touchProgress() {
 	st.mu.Lock()
 	st.rec.Total++
 	st.processed++
-	flush := st.processed%100 == 0
+	now := time.Now()
+	flush := st.processed%100 == 0 || (st.processed%20 == 0 && now.Sub(st.lastProgressFlush) >= 2*time.Second)
+	if flush {
+		st.lastProgressFlush = now
+	}
 	st.mu.Unlock()
 	if flush {
 		st.flushProgress()
diff --git a/internal/service/strm_sync_test.go b/internal/service/strm_sync_test.go
index 8abe99f..c5254a7 100644
--- a/internal/service/strm_sync_test.go
+++ b/internal/service/strm_sync_test.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -493,7 +494,68 @@ func TestWalkRemoteConcurrent(t *testing.T) {
 	if walkErr != nil {
 		t.Fatal(walkErr)
 	}
-	if strmCount != 5 {
-		t.Errorf("生成的 .strm 数量 = %d，期望 5", strmCount)
+		if strmCount != 5 {
+			t.Errorf("生成的 .strm 数量 = %d，期望 5", strmCount)
+		}
 	}
-}
+
+	// TestStrmBatchEnqueueAndConcurrentClaim 测试大规模批量入库及多协程并发认领无死锁
+	func TestStrmBatchEnqueueAndConcurrentClaim(t *testing.T) {
+		svc := testStrmService(t)
+		ctx := context.Background()
+
+		// 1. 批量插入 200 个下载任务
+		tasks := make([]*model.StrmDownloadTask, 0, 200)
+		for i := 0; i < 200; i++ {
+			tasks = append(tasks, &model.StrmDownloadTask{
+				SyncPathID: "test-sync-path",
+				AccountID:  "test-acct",
+				Provider:   model.StrmProvider115,
+				FileName:   filepath.Base(string(rune('a'+i%26))) + ".nfo",
+				LocalPath:  filepath.Join(t.TempDir(), string(rune('a'+i%26)), "test.nfo"),
+				Status:     model.StrmTaskPending,
+			})
+		}
+		if err := svc.repo.StrmDownload.CreateInBatches(ctx, tasks, 50); err != nil {
+			t.Fatalf("CreateInBatches failed: %v", err)
+		}
+
+		// 2. 验证 ActiveLocalPathMap
+		activeMap, err := svc.repo.StrmDownload.GetActiveLocalPathMap(ctx, "test-sync-path")
+		if err != nil {
+			t.Fatalf("GetActiveLocalPathMap failed: %v", err)
+		}
+		if len(activeMap) == 0 {
+			t.Fatal("expected active local path map to have entries")
+		}
+
+		// 3. 模拟 6 个 worker 并发 ClaimPendingDownload
+		claimedCount := 0
+		var claimMu sync.Mutex
+		var wg sync.WaitGroup
+		for w := 0; w < 6; w++ {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				for {
+					batch, err := svc.repo.StrmDownload.ClaimPendingDownload(ctx, 10)
+					if err != nil {
+						t.Errorf("concurrent ClaimPendingDownload failed: %v", err)
+						return
+					}
+					if len(batch) == 0 {
+						return
+					}
+					claimMu.Lock()
+					claimedCount += len(batch)
+					claimMu.Unlock()
+				}
+			}()
+		}
+		wg.Wait()
+
+		if claimedCount != 200 {
+			t.Fatalf("expected all 200 tasks claimed, got %d", claimedCount)
+		}
+	}
+