diff --git a/pipeline_service/rag_client.py b/pipeline_service/rag_client.py
index fbd45d9..767e8c4 100644
--- a/pipeline_service/rag_client.py
+++ b/pipeline_service/rag_client.py
@@ -119,7 +119,7 @@ async def _ensure_downapp(sor):
 async def _load_cached_key(sor, user_id):
     pname = _KEY_PARAM_PREFIX + str(user_id)
     recs = await sor.sqlExe(
-        "SELECT params_value FROM params WHERE id=${n}$", {"n": pname})
+        "SELECT params_value FROM params WHERE params_name=${n}$ LIMIT 1", {"n": pname})
     await sor.sqlExe("COMMIT", {})
     if not recs:
         return ""
@@ -160,10 +160,25 @@ async def get_owner_apikey(owner_id):
         # RC4 加密存 params（与平台密码字段约定一致）
         pname = _KEY_PARAM_PREFIX + str(owner_id)
         enc = _key_encode(key)
-        await sor.sqlExe(
-            "INSERT INTO params (id, params_name, params_value) VALUES (${i}$, ${n}$, ${v}$) "
-            "ON DUPLICATE KEY UPDATE params_value=${v}$",
-            {"i": getID(), "n": pname, "v": enc})
+        # 幂等按 params_name 读-改-写：params 表 params_name 无唯一索引，
+        # 不能用 INSERT...ON DUPLICATE KEY UPDATE（永不触发→重复插行）。
+        # 旧 bug：_load_cached_key 按 id 查、这里按 getID() 随机 id 写，缓存永远 miss
+        # →每次发 key 都新增一行（实测 user-01 堆了 12 行）。2026-09-12 修。
+        exists = await sor.sqlExe(
+            "SELECT id FROM params WHERE params_name=${n}$ ORDER BY id LIMIT 1", {"n": pname})
+        await sor.sqlExe("COMMIT", {})
+        if exists:
+            # 收敛历史重复行：更新首行，删多余行
+            await sor.sqlExe(
+                "UPDATE params SET params_value=${v}$ WHERE id=${i}$",
+                {"v": enc, "i": exists[0].id})
+            await sor.sqlExe(
+                "DELETE FROM params WHERE params_name=${n}$ AND id<>${i}$",
+                {"n": pname, "i": exists[0].id})
+        else:
+            await sor.sqlExe(
+                "INSERT INTO params (id, params_name, params_value) VALUES (${i}$, ${n}$, ${v}$)",
+                {"i": getID(), "n": pname, "v": enc})
         await sor.sqlExe("COMMIT", {})
         _key_cache[owner_id] = key
         return key, ""