fix/various fixes

api/app/core/redis.py

@@ -4,13 +4,13 @@ Redis 客户端与会话/缓存能力：供应用生命周期、会话历史、
 """
 
 import json
-from app.core.logging import get_logger
 from datetime import datetime, timezone
 from typing import Any, Dict, List, Optional
 
 import redis.asyncio as aioredis
 
 from app.core.config import settings
+from app.core.logging import get_logger
 
 logger = get_logger(__name__)
 
@@ -62,6 +62,21 @@ class RedisService:
             logger.error("获取对话历史失败: %s", e)
             return []
 
+    async def set_conversation_history(
+        self, conversation_id: str, history: List[Dict[str, Any]]
+    ) -> bool:
+        """整表覆盖会话历史（用于从 DB 回填），应用 session_ttl。"""
+        try:
+            client = await self.get_client()
+            key = self._conversation_key(conversation_id)
+            await client.setex(
+                key, self.session_ttl, json.dumps(history, ensure_ascii=False)
+            )
+            return True
+        except Exception as e:
+            logger.error("写入对话历史失败: %s", e)
+            return False
+
     async def add_message(
         self,
         conversation_id: str,
@@ -102,6 +117,25 @@ class RedisService:
             logger.error("清除对话历史失败: %s", e)
             return False
 
+    async def delete_keys_matching_pattern(self, pattern: str) -> int:
+        """按 SCAN 批量删除 key，避免阻塞式 KEYS *。"""
+        try:
+            client = await self.get_client()
+            batch: list[str] = []
+            deleted = 0
+
+            async for key in client.scan_iter(match=pattern):
+                batch.append(key)
+                if len(batch) >= 200:
+                    deleted += int(await client.delete(*batch))
+                    batch.clear()
+            if batch:
+                deleted += int(await client.delete(*batch))
+            return deleted
+        except Exception as e:
+            logger.error("按 pattern 删除 Redis key 失败: %s", e)
+            return 0
+
     async def extend_session_ttl(self, conversation_id: str) -> bool:
         try:
             client = await self.get_client()