fix: wrong token number when using qa_model and answer is updated. (#21574)

api/services/dataset_service.py

@@ -2207,6 +2207,7 @@ class SegmentService:
 
                     # calc embedding use tokens
                     if document.doc_form == "qa_model":
+                        segment.answer = args.answer
                         tokens = embedding_model.get_text_embedding_num_tokens(texts=[content + segment.answer])[0]
                     else:
                         tokens = embedding_model.get_text_embedding_num_tokens(texts=[content])[0]