mysql> show create table t2\G
*************************** 1. row ***************************Table: t2
Create Table: CREATE TABLE `t2` (`id` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.07 sec)

CREATE TRIGGER `pt_osc_test_t2_del` AFTER DELETE ON `test`.`t2` FOR EACH ROW DELETE IGNORE FROM `test`.`__t2_new` WHERE `test`.`__t2_new`.`id` <=> OLD.`id`CREATE TRIGGER `pt_osc_test_t2_upd` AFTER UPDATE ON `test`.`t2` FOR EACH ROW REPLACE INTO `test`.`__t2_new` (`id`) VALUES (NEW.`id`)
CREATE TRIGGER `pt_osc_test_t2_ins` AFTER INSERT ON `test`.`t2` FOR EACH ROW REPLACE INTO `test`.`__t2_new` (`id`) VALUES (NEW.`id`)

delimiter //
create procedure p1()
begindeclare v1 int default 1;set autocommit=0;while v1 <=10000000 doinsert into test.t2(id) values(null);set v1=v1+1;if v1%1000 =0 thencommit;end if;end while;
end //
delimiter ;
call p1;

mysql> select count(*),min(id),max(id) from t2;
+----------+---------+----------+
| count(*) | min(id) | max(id)  |
+----------+---------+----------+
| 10000000 |       1 | 10000000 |
+----------+---------+----------+
1 row in set (4.29 sec)

No slaves found.  See --recursion-method if host localhost.localdomain has slaves.
Not checking slave lag because no slaves were found and --check-slave-lag was not specified.
Operation, tries, wait:analyze_table, 10, 1copy_rows, 10, 0.25create_triggers, 10, 1drop_triggers, 10, 1swap_tables, 10, 1update_foreign_keys, 10, 1
Altering `test`.`t2`...
Creating new table...
CREATE TABLE `test`.`___t2_new` (`id` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10000001 DEFAULT CHARSET=utf8
Created new table test.___t2_new OK.
Altering new table...
ALTER TABLE `test`.`___t2_new` ADD COLUMN c1 DATETIME
Altered `test`.`___t2_new` OK.
2016-10-23T20:24:13 Creating triggers...
CREATE TRIGGER `pt_osc_test_t2_del` AFTER DELETE ON `test`.`t2` FOR EACH ROW DELETE IGNORE FROM `test`.`___t2_new` WHERE `test`.`___t
2_new`.`id` <=> OLD.`id`CREATE TRIGGER `pt_osc_test_t2_upd` AFTER UPDATE ON `test`.`t2` FOR EACH ROW REPLACE INTO `test`.`___t2_new` (`id`) VALUES (NEW.`id`)
CREATE TRIGGER `pt_osc_test_t2_ins` AFTER INSERT ON `test`.`t2` FOR EACH ROW REPLACE INTO `test`.`___t2_new` (`id`) VALUES (NEW.`id`)
2016-10-23T20:24:13 Created triggers OK.
2016-10-23T20:24:13 Copying approximately 9429750 rows...
INSERT LOW_PRIORITY IGNORE INTO `test`.`___t2_new` (`id`) SELECT `id` FROM `test`.`t2` FORCE INDEX(`PRIMARY`) WHERE ((`id` >= ?)) AND((`id` <= ?)) LOCK IN SHARE MODE /*pt-online-schema-change 2456 copy nibble*/SELECT /*!40001 SQL_NO_CACHE */ `id` FROM `test`.`t2` FORCE INDEX(`PRIMARY`) WHERE ((`id` >= ?)) ORDER BY `id` LIMIT ?, 2 /*next chun
k boundary*/Copying `test`.`t2`:  29% 01:12 remain
Copying `test`.`t2`:  52% 00:54 remain
Copying `test`.`t2`:  76% 00:27 remain
2016-10-23T20:26:22 Copied rows OK.
2016-10-23T20:26:22 Analyzing new table...
2016-10-23T20:26:23 Swapping tables...
RENAME TABLE `test`.`t2` TO `test`.`_t2_old`, `test`.`___t2_new` TO `test`.`t2`
2016-10-23T20:26:24 Swapped original and new tables OK.
2016-10-23T20:26:24 Dropping old table...
DROP TABLE IF EXISTS `test`.`_t2_old`
2016-10-23T20:26:24 Dropped old table `test`.`_t2_old` OK.
2016-10-23T20:26:24 Dropping triggers...
DROP TRIGGER IF EXISTS `test`.`pt_osc_test_t2_del`;
DROP TRIGGER IF EXISTS `test`.`pt_osc_test_t2_upd`;
DROP TRIGGER IF EXISTS `test`.`pt_osc_test_t2_ins`;
2016-10-23T20:26:24 Dropped triggers OK.
Successfully altered `test`.`t2`.

 mysql -e 'update test.t2 set id=-1 where id=1'mysql -e 'update test.t2 set id=-2 where id=2'mysql -e 'update test.t2 set id=-3 where id=3'mysql -e 'update test.t2 set id=-4 where id=4'mysql -e 'update test.t2 set id=-5 where id=5'mysql -e 'update test.t2 set id=-6 where id=6'mysql -e 'update test.t2 set id=-7 where id=7'mysql -e 'update test.t2 set id=-8 where id=8'mysql -e 'update test.t2 set id=-9 where id=9'mysql -e 'update test.t2 set id=-10 where id=10'

mysql> select count(*),min(id),max(id) from t2;
+----------+---------+----------+
| count(*) | min(id) | max(id)  |
+----------+---------+----------+
| 10000010 |     -10 | 10000000 |
+----------+---------+----------+
1 row in set (3.00 sec)mysql> select * from t2 order by id limit 20;
+-----+------+
| id  | c1   |
+-----+------+
| -10 | NULL |
|  -9 | NULL |
|  -8 | NULL |
|  -7 | NULL |
|  -6 | NULL |
|  -5 | NULL |
|  -4 | NULL |
|  -3 | NULL |
|  -2 | NULL |
|  -1 | NULL |
|   1 | NULL |
|   2 | NULL |
|   3 | NULL |
|   4 | NULL |
|   5 | NULL |
|   6 | NULL |
|   7 | NULL |
|   8 | NULL |
|   9 | NULL |
|  10 | NULL |
+-----+------+
20 rows in set (0.08 sec)

CREATE TRIGGER `pt_osc_test_t2_del` AFTER DELETE ON `test`.`t2` FOR EACH ROW DELETE IGNORE FROM `test`.`_t2_new` WHERE `test`.`_t2_new`.`id` <=> OLD.`id`

mysql> create table t3(id int,name varchar(10));
Query OK, 0 rows affected (0.08 sec)mysql> insert into t3 values(1,'a');
Query OK, 1 row affected (0.05 sec)mysql> replace into t3 values(1,'b');
Query OK, 1 row affected (0.06 sec)mysql> select * from t3;
+------+------+
| id   | name |
+------+------+
|    1 | a    |
|    1 | b    |
+------+------+
2 rows in set (0.00 sec)mysql> alter table t3 modify id int primary key;
ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY'
mysql> delete from t3 where id=1 and name='b';
Query OK, 1 row affected (0.07 sec)mysql> alter table t3 modify id int primary key;
Query OK, 0 rows affected (0.24 sec)
Records: 0  Duplicates: 0  Warnings: 0mysql> select * from t3;
+----+------+
| id | name |
+----+------+
|  1 | a    |
+----+------+
1 row in set (0.00 sec)mysql> replace into t3 values(1,'b');
Query OK, 2 rows affected (0.01 sec)mysql> select * from t3;
+----+------+
| id | name |
+----+------+
|  1 | b    |
+----+------+
1 row in set (0.01 sec)