Use Infinity single-field-multi-index (#11444)

### What problem does this PR solve?

Use Infinity single-field-multi-index

### Type of change

- [x] Refactoring
- [x] Performance Improvement

api/ragflow_server.py

@@ -20,7 +20,6 @@
 
 from common.log_utils import init_root_logger
 from plugin import GlobalPluginManager
-init_root_logger("ragflow_server")
 
 import logging
 import os
@@ -30,6 +29,7 @@ import time
 import traceback
 import threading
 import uuid
+import faulthandler
 
 from api.apps import app, smtp_mail_server
 from api.db.runtime_config import RuntimeConfig
@@ -73,6 +73,8 @@ def signal_handler(sig, frame):
     sys.exit(0)
 
 if __name__ == '__main__':
+    faulthandler.enable()
+    init_root_logger("ragflow_server")
     logging.info(r"""
         ____   ___    ______ ______ __
        / __ \ /   |  / ____// ____// /____  _      __