MySQL - 5. 数据库管理 - 5.3. mysqld：MySQL服务器 - 5.3.3. 服务器系统变量 - max_allowed_packet

max_allowed_packet

Option Sets Variable
选项集变量 Yes, max_allowed_packet
是

Variable Name
变量名称 max_allowed_packet

Variable Scope
变量范围 Both
都有

Dynamic Variable
动态变量 Yes
是

Value Set
值集

Type 类型	`numeric 数字`
Default 默认值	`1048576`
Range 范围	`1024-1073741824`

The maximum size of one packet or any generated/intermediate string.

任何生成的/中间字符串的最大大小。

The packet message buffer is initialized to net_buffer_length bytes, but can grow up to max_allowed_packet bytes when needed. This value by default is small, to catch large (possibly incorrect) packets.

包消息缓冲区初始化为net_buffer_length字节，但需要时可以增长到max_allowed_packet字节。该值默认很小，以捕获大的(可能是错误的)数据包。

You must increase this value if you are using large BLOB columns or long strings. It should be as big as the largest BLOB you want to use. The protocol limit for max_allowed_packet is 1GB. The value should be a multiple of 1024; non-multiples are rounded down to the nearest multiple.

如果你使用大的BLOB 列或长字符串，你必须增加该值。应同你想要使用的最大的BLOB一样大。max_allowed_packet的协议限制为1GB。该值应当是1024的倍数，非整数倍将缩小至最接近的整数倍。

As of MySQL 5.1.31, the session value of this variable is read only. Before 5.1.31, setting the session value is allowed but has no effect.

对于MySQL 5.1.31，该变量的会话值是只读的，在5.1.31之间，允许设置会话值，但不起作用。