##错误: ERROR 1044 (42000): Access denied for user ‘root’@’%’ to database ‘dede’
mysql> create database dede;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47299
Current database: NONE
Query OK, 1 row affected (0.00 sec)
mysql> grant all privileges on dede.* to ‘dede’@’localhost’ identified by ‘dede123’; ##授权时执行失败
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47302
Current database: NONE
ERROR 1044 (42000): Access denied for user ‘root’@’%’ to database ‘dede’ ##拒绝访问的用户
解决：
mysql> select Grant_priv from mysql.user where Host=’localhost’; ##N代表没有权限
+————+
| Grant_priv |
+————+
| N |
| N |
| N |
+————+
3 rows in set (0.00 sec)
mysql> select Grant_priv from mysql.user where Host=’127.0.0.1′;
+————+
| Grant_priv |
+————+
| Y |
+————+
1 row in set (0.00 sec)
mysql> update mysql.user set Grant_priv=’Y’ where Host=’localhost’;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47312
Current database: NONE
Query OK, 3 rows affected (0.01 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> select Grant_priv from mysql.user where Host=’localhost’;
+————+
| Grant_priv |
+————+
| Y |
| Y |
| Y |
+————+
3 rows in set (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> grant all privileges on dede.* to ‘dede’@’localhost’ identified by ‘dede123’;
ERROR 1044 (42000): Access denied for user ‘root’@’%’ to database ‘dede’
mysql> show variables like ‘read_only’
-> ;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47323
Current database: NONE
+—————+——-+
| Variable_name | Value |
+—————+——-+
| read_only | OFF |
+—————+——-+
1 row in set (0.00 sec)
mysql> show global variables like ‘max_allowed_packet’; ##查看max_allowed_packet的值，默认是1MB
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47339
Current database: NONE
+——————–+———+
| Variable_name | Value |
+——————–+———+
| max_allowed_packet | 1048576 |
+——————–+———+
1 row in set (0.00 sec)
mysql> set global max_allowed_packet=1024102416; ##临时修改max_allowed_packet值为16MB，重启失效
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47341
Current database: NONE
Query OK, 0 rows affected (0.00 sec)
mysql> show global variables like ‘max_allowed_packet’; ##查看.,临时已生效
+——————–+———-+
| Variable_name | Value |
+——————–+———-+
| max_allowed_packet | 16777216 |
+——————–+———-+
1 row in set (0.00 sec)
mysql> grant all privileges on dede.* to ‘dede’@’localhost’ identified by ‘dede123’; ###grant授权用户成功
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect…
Connection id: 47347
Current database: NONE
Query OK, 0 rows affected (0.00 sec)
mysql> exit
Bye
###永久修改参数
[root@118 ~]# vim /etc/my.cnf
[mysqld]
max_allowed_packet = 16M
mysql 重启生效
