perf: add get_all_kb_doc_count func to simplify kb.doc_num updating (#10169)

### What problem does this PR solve?

Add get_all_kb_doc_count func to simplify kb.doc_num updating.

### Type of change

- [x] Performance Improvement

api/db/init_data.py

@@ -144,8 +144,9 @@ def init_llm_factory():
             except Exception:
                 pass
             break
+    doc_count = DocumentService.get_all_kb_doc_count()
     for kb_id in KnowledgebaseService.get_all_ids():
-        KnowledgebaseService.update_document_number_in_init(kb_id=kb_id, doc_num=DocumentService.get_kb_doc_count(kb_id))
+        KnowledgebaseService.update_document_number_in_init(kb_id=kb_id, doc_num=doc_count.get(kb_id, 0))
 
 
 

api/db/services/document_service.py

@@ -660,8 +660,16 @@ class DocumentService(CommonService):
     @classmethod
     @DB.connection_context()
     def get_kb_doc_count(cls, kb_id):
-        return len(cls.model.select(cls.model.id).where(
+        return cls.model.select().where(cls.model.kb_id == kb_id).count()
-            cls.model.kb_id == kb_id).dicts())
+
+    @classmethod
+    @DB.connection_context()
+    def get_all_kb_doc_count(cls):
+        result = {}
+        rows = cls.model.select(cls.model.kb_id, fn.COUNT(cls.model.id).alias('count')).group_by(cls.model.kb_id)
+        for row in rows:
+            result[row.kb_id] = row.count
+        return result
 
     @classmethod
     @DB.connection_context()