Mysql中alter权限的隐患

MySQL测试环境中一张表被清空,检查binglog并没有发现有delte，drop，truncate操作。
$mysqlbinlog test-150-bin.251369 |grep -i -E  -B3 'drop|delete|truncate'

检查了今天所有的binlog都没发现有delete,drop,truncate操作。
而且也排除了有人用临时关闭二进制日志的方式进行的恶意操作，因为没有权限。

看了一下表结构，居然发现ENGINE=BLACKHOLE
mysql> show create table t;
+-------+----------------------------------------------------------------------------------------+
| Table | Create Table                                                                           |
+-------+----------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `aa` int(10) DEFAULT NULL
) ENGINE=BLACKHOLE DEFAULT CHARSET=utf8 |
+-------+----------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

过滤binlog中的alter，果然发现有对这个表的alter操作，把表的engine改为了BLACKHOLE

$mysqlbinlog test-150-bin.251369 |grep -i -E  -B3 'drop|delete|truncate|alter'
#141210 12:09:10 server id 150  end_log_pos 448502 CRC32 0xea5ee5cc     Query   thread_id=530   exec_time=0     error_code=0
SET TIMESTAMP=1418202550/*!*/;
ALTER TABLE `t` ENGINE=BLACKHOLE

 

模拟一下这个操作：
mysql> show create table t;
+-------+-----------------------------------------------+
| Table | Create Table                                  |
+-------+-----------------------------------------------+
| t     | CREATE TABLE `t` (
  `aa` int(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-----------------------------------------------+
1 row in set (0.02 sec)

 

mysql> insert into t values(1);
Query OK, 1 row affected (0.02 sec)

mysql> insert into t values(2);
Query OK, 1 row affected (0.01 sec)

mysql> select * from t;
+------+
| aa   |
+------+
|    1 |
|    2 |
+------+
2 rows in set (0.00 sec)

mysql> ALTER TABLE `t` ENGINE=BLACKHOLE;
Query OK, 2 rows affected (0.02 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from t;
Empty set (0.16 sec)

结论：不能把alter的权限赋给普通用户。