三个命令：
1、进入mysql ：

mysql -u root -p

2、查看buffersize：

show variables like ‘%sort_buffer_size%’;

3、设置大小：

SET GLOBAL sort_buffer_size = 1024*1024;

看见Query OK 就成功了

操作入下

☁  ~  mysql -u root -p
Enter password: 
Welcome to the MySQL  ;


mysql> show variables like '%sort_buffer_size%'; 
+-------------------------+---------+
| Variable_name           | Value   |
+-------------------------+---------+
| innodb_sort_buffer_size | 1048576 |
| myisam_sort_buffer_size | 8388608 |
| sort_buffer_size        | 65536   |
+-------------------------+---------+
3 rows in set (0.02 sec)


mysql> SET GLOBAL sort_buffer_size = 1024*1024;
Query OK, 0 rows affected (0.00 sec)