Refa: asyncio.to_thread to ThreadPoolExecutor to break thread limitat… (#12716)

### Type of change

- [x] Refactoring

api/apps/chunk_app.py

@@ -13,7 +13,6 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 #
-import asyncio
 import datetime
 import json
 import re
@@ -27,8 +26,14 @@ from api.db.services.llm_service import LLMBundle
 from common.metadata_utils import apply_meta_data_filter
 from api.db.services.search_service import SearchService
 from api.db.services.user_service import UserTenantService
-from api.utils.api_utils import get_data_error_result, get_json_result, server_error_response, validate_request, \
-    get_request_json
+from api.utils.api_utils import (
+    get_data_error_result,
+    get_json_result,
+    server_error_response,
+    validate_request,
+    get_request_json,
+)
+from common.misc_utils import thread_pool_exec
 from rag.app.qa import beAdoc, rmPrefix
 from rag.app.tag import label_question
 from rag.nlp import rag_tokenizer, search
@@ -38,7 +43,6 @@ from common.constants import RetCode, LLMType, ParserType, PAGERANK_FLD
 from common import settings
 from api.apps import login_required, current_user
 
-
 @manager.route('/list', methods=['POST'])  # noqa: F821
 @login_required
 @validate_request("doc_id")
@@ -190,7 +194,7 @@ async def set():
                 settings.STORAGE_IMPL.put(bkt, name, image_binary)
             return get_json_result(data=True)
 
-        return await asyncio.to_thread(_set_sync)
+        return await thread_pool_exec(_set_sync)
     except Exception as e:
         return server_error_response(e)
 
@@ -213,7 +217,7 @@ async def switch():
                     return get_data_error_result(message="Index updating failure")
             return get_json_result(data=True)
 
-        return await asyncio.to_thread(_switch_sync)
+        return await thread_pool_exec(_switch_sync)
     except Exception as e:
         return server_error_response(e)
 
@@ -255,7 +259,7 @@ async def rm():
                     settings.STORAGE_IMPL.rm(doc.kb_id, cid)
             return get_json_result(data=True)
 
-        return await asyncio.to_thread(_rm_sync)
+        return await thread_pool_exec(_rm_sync)
     except Exception as e:
         return server_error_response(e)
 
@@ -314,7 +318,7 @@ async def create():
                 doc.id, doc.kb_id, c, 1, 0)
             return get_json_result(data={"chunk_id": chunck_id})
 
-        return await asyncio.to_thread(_create_sync)
+        return await thread_pool_exec(_create_sync)
     except Exception as e:
         return server_error_response(e)