在autocommit=1的情况下，开启一个事务，如果里面有DDL语句，那么事务开始到DDL语句之间的DML语句都会被提交。再开启新的事务。可以从binlog中看出

session语句：

09:26:04 root@localhost:[testdb] mysql.sock>select * from t2;

+——+——–+——-+

| id | course | score |

+——+——–+——-+

| 1 | math | 0 |

| 2 | ch | 0 |

| 3 | eng | 0 |

+——+——–+——-+

3 rows in set (0.00 sec)

09:26:10 root@localhost:[testdb] mysql.sock> begin;

Query OK, 0 rows affected (0.00 sec)

09:26:18 root@localhost:[testdb] mysql.sock> delete from t2 where id=2;

Query OK, 1 row affected (0.05 sec)

09:26:30 root@localhost:[testdb] mysql.sock> alter table t2 drop column score;

Query OK, 0 rows affected (0.11 sec)

Records: 0 Duplicates: 0 Warnings: 0

09:26:43 root@localhost:[testdb] mysql.sock> delete from t2 where id=3;

Query OK, 1 row affected (0.00 sec)

09:26:53 root@localhost:[testdb] mysql.sock> delete from t2 where id=1;

Query OK, 1 row affected (0.03 sec)

09:27:30 root@localhost:[testdb] mysql.sock>rollback;

Query OK, 0 rows affected (0.00 sec)

09:27:37 root@localhost:[testdb] mysql.sock>select * from t2;

Empty set (0.00 sec)

mysqlbinlog解析：

[ root@zejin240 mysql]# mysqlbinlog –no-defaults -v –base64-output=DECODE-ROWS good.000001

/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;

/*!40019 SET @@session.max_insert_delayed_threads=0*/;

/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;

DELIMITER /*!*/;

# at 4

#160510 9:26:03 server id 4 end_log_pos 120 CRC32 0xfb18f530 Start: binlog v 4, server v 5.6.16-log created 160510 9:26:03 at startup

# Warning: this binlog is either in use or was not closed properly.

ROLLBACK/*!*/;

# at 120

#160510 9:26:30 server id 4 end_log_pos 194 CRC32 0x4613aabe Query thread_id=1490 exec_time=0 error_code=0

SET TIMESTAMP=1462843590/*!*/;

SET @@session.pseudo_thread_id=1490/*!*/;

SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;

SET @@session.sql_mode=1075838976/*!*/;

SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;

/*!\C utf8 *//*!*/;

SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/;

SET @@session.lc_time_names=0/*!*/;

SET @@session.collation_database=DEFAULT/*!*/;

BEGIN

/*!*/;

# at 194

#160510 9:26:30 server id 4 end_log_pos 245 CRC32 0x12aee719 Table_map: `testdb`.`t2` mapped to number 100

# at 245

#160510 9:26:30 server id 4 end_log_pos 292 CRC32 0x42bb4b1e Delete_rows: table id 100 flags: STMT_END_F

### DELETE FROM `testdb`.`t2`

### WHERE

### @1=2

### @2=’ch’

### @3=0

# at 292

#160510 9:26:43 server id 4 end_log_pos 323 CRC32 0x7f4b17a2 Xid = 4683

COMMIT/*!*/;

# at 323

#160510 9:26:43 server id 4 end_log_pos 433 CRC32 0x3da26437 Query thread_id=1490 exec_time=0 error_code=0

use `testdb`/*!*/;

SET TIMESTAMP=1462843603/*!*/;

alter table t2 drop column score

/*!*/;

# at 433

#160510 9:26:53 server id 4 end_log_pos 507 CRC32 0xaf228c7f Query thread_id=1490 exec_time=0 error_code=0

SET TIMESTAMP=1462843613/*!*/;

BEGIN

/*!*/;

# at 507

#160510 9:26:53 server id 4 end_log_pos 557 CRC32 0x98b09e6b Table_map: `testdb`.`t2` mapped to number 108

# at 557

#160510 9:26:53 server id 4 end_log_pos 601 CRC32 0x56abcace Delete_rows: table id 108 flags: STMT_END_F

### DELETE FROM `testdb`.`t2`

### WHERE

### @1=3

### @2=’eng’

# at 601

#160510 9:26:53 server id 4 end_log_pos 632 CRC32 0x41e6e24f Xid = 4754

COMMIT/*!*/;

# at 632

#160510 9:27:30 server id 4 end_log_pos 706 CRC32 0x4916f7a0 Query thread_id=1490 exec_time=0 error_code=0

SET TIMESTAMP=1462843650/*!*/;

BEGIN

/*!*/;

# at 706

#160510 9:27:30 server id 4 end_log_pos 756 CRC32 0x15098e83 Table_map: `testdb`.`t2` mapped to number 108

# at 756

#160510 9:27:30 server id 4 end_log_pos 801 CRC32 0x2bc1b8aa Delete_rows: table id 108 flags: STMT_END_F

### DELETE FROM `testdb`.`t2`

### WHERE

### @1=1

### @2=’math’

# at 801

#160510 9:27:30 server id 4 end_log_pos 832 CRC32 0x9ce9b647 Xid = 4870

COMMIT/*!*/;

DELIMITER ;

# End of log file

ROLLBACK /* added by mysqlbinlog */;

/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;

/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;