DROP TABLE IF EXISTS t1; create table t1 (a int key, b int) engine ndb; create table t2 (a int key, b int) engine ndb; insert into t1 values (0,0),(1,1),(2,2); insert into t2 select * from t1; begin; set transaction_allow_batching=1; update t1 set b=0 where a=2; commit; @ndb_execute_count:=VARIABLE_VALUE-@ndb_init_execute_count 1 select * from t1 order by a; a b 0 0 1 1 2 0 With batching only 1 roundtrip begin; set transaction_allow_batching=1; insert into t1 values (10,10); insert into t2 values (10,10); commit; @ndb_execute_count:=VARIABLE_VALUE-@ndb_init_execute_count 1 select * from t1 order by a; a b 0 0 1 1 2 0 10 10 Without batching only 3 roundtrips begin; set transaction_allow_batching=0; insert into t1 values (11,11); insert into t2 values (11,11); commit; @ndb_execute_count:=VARIABLE_VALUE-@ndb_init_execute_count 3 select * from t1 order by a; a b 0 0 1 1 2 0 10 10 11 11 drop table t1, t2;