fix segment query index not effect (#17704)

api/core/rag/datasource/retrieval_service.py

 from typing import Optional
 
 from flask import Flask, current_app
+from sqlalchemy import and_, or_
 from sqlalchemy.orm import load_only
+from sqlalchemy.sql.expression import false
 
 from configs import dify_config
 from core.rag.data_post_processor.data_post_processor import DataPostProcessor
             child_chunks = db.session.query(ChildChunk).filter(ChildChunk.index_node_id.in_(child_index_node_ids)).all()
             child_chunk_map = {chunk.index_node_id: chunk for chunk in child_chunks}
 
-            # Batch query DocumentSegment with unified conditions
+            segment_ids_from_child = [chunk.segment_id for chunk in child_chunks]
+            segment_conditions = []
+
+            if index_node_ids:
+                segment_conditions.append(DocumentSegment.index_node_id.in_(index_node_ids))
+
+            if segment_ids_from_child:
+                segment_conditions.append(DocumentSegment.id.in_(segment_ids_from_child))
+
+            if segment_conditions:
+                filter_expr = or_(*segment_conditions)
+            else:
+                filter_expr = false()
+
             segment_map = {
                 segment.id: segment
                 for segment in db.session.query(DocumentSegment)
                 .filter(
-                    (
-                        DocumentSegment.index_node_id.in_(index_node_ids)
-                        | DocumentSegment.id.in_([chunk.segment_id for chunk in child_chunks])
-                    ),
-                    DocumentSegment.enabled == True,
-                    DocumentSegment.status == "completed",
+                    and_(
+                        filter_expr,
+                        DocumentSegment.enabled == True,
+                        DocumentSegment.status == "completed",
+                    )
                 )
                 .options(
                     load_only(