Transaction:
TRANSACTION 0 3358, ACTIVE 0 sec, process no 5202, OS thread id 1141152064 inserting, thread declared inside InnoDB 500
mysql tables in use 1, locked 1
3 lock struct(s), heap size 368, undo log entries 1
MySQL thread id 6, query id 162 localhost root update
insert into t2(a) values(1)
Foreign key constraint fails for table `test/t2`:
,
  CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`a`) REFERENCES `t1` (`a`)
Trying to add in child table, in index `a` tuple:
DATA TUPLE: 2 fields;
 0: len 4; hex 80000001; asc     ;; 1: len 6; hex 000000000200; asc       ;;

But in parent table `test/t1`, in index `PRIMARY`,
the closest match we can find is record:
PHYSICAL RECORD: n_fields 1; compact format; info bits 0
 0: len 8; hex 696e66696d756d00; asc infimum ;;