diff --git a/rag/nlp/search.py b/rag/nlp/search.py
index 154d5850d..a24f7a71d 100644
--- a/rag/nlp/search.py
+++ b/rag/nlp/search.py
@@ -46,6 +46,9 @@ class Dealer:
 
     def get_vector(self, txt, emb_mdl, topk=10, similarity=0.1):
         qv, _ = emb_mdl.encode_queries(txt)
+        shape = np.array(qv).shape
+        if len(shape) > 1:
+            raise Exception(f"Dealer.get_vector returned array's shape {shape} doesn't match expectation(exact one dimension).")
         embedding_data = [float(v) for v in qv]
         vector_column_name = f"q_{len(embedding_data)}_vec"
         return MatchDenseExpr(vector_column_name, embedding_data, 'float', 'cosine', topk, {"similarity": similarity})