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

### Type of change

- [x] Refactoring

api/apps/kb_app.py

@@ -17,7 +17,6 @@ import json
 import logging
 import random
 import re
-import asyncio
 
 from quart import request
 import numpy as np
@@ -30,8 +29,15 @@ from api.db.services.file_service import FileService
 from api.db.services.pipeline_operation_log_service import PipelineOperationLogService
 from api.db.services.task_service import TaskService, GRAPH_RAPTOR_FAKE_DOC_ID
 from api.db.services.user_service import TenantService, UserTenantService
-from api.utils.api_utils import get_error_data_result, server_error_response, get_data_error_result, validate_request, not_allowed_parameters, \
-    get_request_json
+from api.utils.api_utils import (
+    get_error_data_result,
+    server_error_response,
+    get_data_error_result,
+    validate_request,
+    not_allowed_parameters,
+    get_request_json,
+)
+from common.misc_utils import thread_pool_exec
 from api.db import VALID_FILE_TYPES
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.db_models import File
@@ -44,7 +50,6 @@ from common import settings
 from common.doc_store.doc_store_base import OrderByExpr
 from api.apps import login_required, current_user
 
-
 @manager.route('/create', methods=['post'])  # noqa: F821
 @login_required
 @validate_request("name")
@@ -90,7 +95,7 @@ async def update():
                 message="The chunking method Tag has not been supported by Infinity yet.",
                 data=False,
             )
-        if "pagerank" in req:
+        if "pagerank" in req and req["pagerank"] > 0:
             return get_json_result(
                 code=RetCode.DATA_ERROR,
                 message="'pagerank' can only be set when doc_engine is elasticsearch",
@@ -144,7 +149,7 @@ async def update():
 
         if kb.pagerank != req.get("pagerank", 0):
             if req.get("pagerank", 0) > 0:
-                await asyncio.to_thread(
+                await thread_pool_exec(
                     settings.docStoreConn.update,
                     {"kb_id": kb.id},
                     {PAGERANK_FLD: req["pagerank"]},
@@ -153,7 +158,7 @@ async def update():
                 )
             else:
                 # Elasticsearch requires PAGERANK_FLD be non-zero!
-                await asyncio.to_thread(
+                await thread_pool_exec(
                     settings.docStoreConn.update,
                     {"exists": PAGERANK_FLD},
                     {"remove": PAGERANK_FLD},
@@ -312,7 +317,7 @@ async def rm():
                     settings.STORAGE_IMPL.remove_bucket(kb.id)
             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)