diff --git a/src/variant.rs b/src/variant.rs
index f3be34f..d8157c8 100644
--- a/src/variant.rs
+++ b/src/variant.rs
@@ -65,6 +65,7 @@ impl Variant {
         let db = get_mongo!();
 
         let mut ses = db.start_session(None).await.unwrap();
+        ses.start_transaction(None).await.unwrap();
 
         let col: mongodb::Collection<mongodb::bson::Document> =
             ses.client().database("cdb").collection("supply");