drop table if exists t1;
CREATE TABLE `t1` (
  `a25` int,
  `col605` int,
  `col609` int,
  PRIMARY KEY (`a25`,`col609`),
  UNIQUE KEY (`col605`)
) ENGINE=InnoDB;


in 15 threads, where ? is random smallint. autocommit=1 and nobody starts/commits trx.
insert ignore into `t1` set `a25`=?,`col605`=abs(?) % 1,`col609`=abs(?)

------------------------
LATEST DETECTED DEADLOCK
------------------------
100421  9:35:04
*** (1) TRANSACTION:
TRANSACTION 129E30, ACTIVE 0 sec, OS thread id 4572 inserting
mysql tables in use 1, locked 1
LOCK WAIT 4 lock struct(s), heap size 1216, 2 row lock(s)
MySQL thread id 34, query id 25668 192.168.1.100 root update
insert ignore into `t1` set `a25`=27772,`col605`=abs(5503) % 1,`col609`=abs(-18536)
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 50 n bits 72 index `PRIMARY` of table `test`.`t1` trx id 129E30 lock_mode X locks gap before rec insert intention waiting
Record lock, heap no 5 PHYSICAL RECORD: n_fields 5; compact format; info bits 0
 0: len 4; hex 8000755e; asc   u^;;
 1: len 4; hex 80000391; asc     ;;
 2: len 6; hex 000000129e3c; asc      <;;
 3: len 7; hex 80000012ca0084; asc        ;;
 4: len 4; hex 80000000; asc     ;;

*** (2) TRANSACTION:
TRANSACTION 129E3B, ACTIVE 0 sec, OS thread id 628 inserting
mysql tables in use 1, locked 1
4 lock struct(s), heap size 1216, 2 row lock(s)
MySQL thread id 37, query id 25679 192.168.1.100 root update
insert ignore into `t1` set `a25`=27772,`col605`=abs(5503) % 1,`col609`=abs(-18536)
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 0 page no 50 n bits 72 index `PRIMARY` of table `test`.`t1` trx id 129E3B lock_mode X locks gap before rec
Record lock, heap no 5 PHYSICAL RECORD: n_fields 5; compact format; info bits 0
 0: len 4; hex 8000755e; asc   u^;;
 1: len 4; hex 80000391; asc     ;;
 2: len 6; hex 000000129e3c; asc      <;;
 3: len 7; hex 80000012ca0084; asc        ;;
 4: len 4; hex 80000000; asc     ;;

*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 50 n bits 72 index `PRIMARY` of table `test`.`t1` trx id 129E3B lock_mode X locks gap before rec insert intention waiting
Record lock, heap no 5 PHYSICAL RECORD: n_fields 5; compact format; info bits 0
 0: len 4; hex 8000755e; asc   u^;;
 1: len 4; hex 80000391; asc     ;;
 2: len 6; hex 000000129e3c; asc      <;;
 3: len 7; hex 80000012ca0084; asc        ;;
 4: len 4; hex 80000000; asc     ;;

*** WE ROLL BACK TRANSACTION (2)
------------
TRANSACTIONS
------------
Trx id counter 129E3F