fix(batch_create_segment_to_index_task): count max_position in memory. (#12929)

api/models/dataset.py

@@ -13,6 +13,7 @@ from typing import Any, cast
 
 from sqlalchemy import func
 from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped
 
 from configs import dify_config
 from core.rag.retrieval.retrieval_methods import RetrievalMethod
@@ -515,7 +516,7 @@ class DocumentSegment(db.Model):  # type: ignore[name-defined]
     tenant_id = db.Column(StringUUID, nullable=False)
     dataset_id = db.Column(StringUUID, nullable=False)
     document_id = db.Column(StringUUID, nullable=False)
-    position = db.Column(db.Integer, nullable=False)
+    position: Mapped[int]
     content = db.Column(db.Text, nullable=False)
     answer = db.Column(db.Text, nullable=True)
     word_count = db.Column(db.Integer, nullable=False)