diff --git a/__tests__/TestSqlCommonRaw.ml b/__tests__/TestSqlCommonRaw.ml
index 9912541..7104c72 100644
--- a/__tests__/TestSqlCommonRaw.ml
+++ b/__tests__/TestSqlCommonRaw.ml
@@ -155,4 +155,41 @@ describe "Raw SQL Query Test Sequence" (fun () ->
         |> finish
     )
   );
-);
+
+  testAsync "Rollback batch insert on duplicate key" (fun finish ->
+    let id_0 = string_of_int (Js.Math.random_int 0 (Js.Int.max - 1)) in
+    let code_0 = {j|unique-value-$id_0|j} in
+    let sql = "INSERT INTO test.simple (id, code) VALUES (?, ?)" in
+    let params = `Positional (Json.Encode.array Json.Encode.string [| id_0; code_0 |]) in
+    Sql.mutate conn ~sql ~params (fun res ->
+      match res with
+      | `Error e -> let _ = Js.log e in finish (fail "see log")
+      | `Mutation (_, _) ->
+        let id_1 = string_of_int (Js.Math.random_int 0 (Js.Int.max - 1)) in
+        let code_1 = {j|unique-value-$id_1|j} in
+        let batch_size = 1 in
+        let table = "test.simple" in
+        let columns = Belt.Array.map [|"id"; "code"|] Json.Encode.string in 
+        (* order is important here *)
+        let rows = Belt.Array.map [|
+          Json.Encode.array Json.Encode.string [| id_1; code_1 |];
+          Json.Encode.array Json.Encode.string [| id_0; code_0 |];
+        |] (fun a -> a) in
+        Sql.mutate_batch conn ~batch_size ~table ~columns ~rows (fun res ->
+          match res with
+          | `Mutation (rows, id) -> let _ = Js.log3 "mutation should have failed" rows id in
+            finish (fail "see log")
+          | `Error _ -> Sql.query conn ~sql:{j|SELECT * FROM test.simple WHERE code='$(code_1)'|j} (fun res ->
+            match res with
+            | `Error e -> let _ = Js.log e in finish (fail "see log")
+            | `Select (rows, _) ->
+              rows
+              |> Expect.expect
+              |> Expect.toHaveLength 0
+              |> finish
+            )
+        )
+    );
+  );
+)
+
diff --git a/__tests__/TestUtil.ml b/__tests__/TestUtil.ml
index 0af31a9..f10f1f8 100644
--- a/__tests__/TestUtil.ml
+++ b/__tests__/TestUtil.ml
@@ -1,6 +1,15 @@
 
+let env = Node.Process.process##env
+let host = Belt.Option.getWithDefault (Js.Dict.get env "MYSQL_HOST") "localhost"
+let port = int_of_string (Belt.Option.getWithDefault (Js.Dict.get env "MYSQL_PORT") "3306")
+let user = Belt.Option.getWithDefault (Js.Dict.get env "MYSQL_USER") "root"
+let password = Belt.Option.getWithDefault (Js.Dict.get env "MYSQL_PASSWORD") "password"
+let database = Belt.Option.getWithDefault (Js.Dict.get env "MYSQL_DATABASE") "test"
+
 let connect _ = MySql2.connect
-  ~host:"127.0.0.1"
-  ~port:3306
-  ~user:"root"
+  ~host
+  ~port
+  ~user
+  ~password
+  ~database
   ()
diff --git a/src/SqlCommonBatchInsert.ml b/src/SqlCommonBatchInsert.ml
index fe27006..8ec57fd 100644
--- a/src/SqlCommonBatchInsert.ml
+++ b/src/SqlCommonBatchInsert.ml
@@ -67,7 +67,12 @@ let insert execute ?batch_size ~table ~columns ~rows user_cb =
     | None -> 1000
     | Some(s) -> s
   in
-  let fail = (fun e -> user_cb (`Error e)) in
+  let fail = (fun err -> rollback ~execute
+    ~fail:(fun err -> user_cb (`Error err))
+    ~ok:(fun _ _ -> user_cb (`Error err))
+    ()
+  )
+  in
   let complete = (fun count id ->
     let ok = (fun _ _ -> user_cb (`Mutation (count, id)))
     in