MySQL 切换数据库、用户卡死：“You can turn off this feature to get a quicker startup with -A“处理方法

数据量很大的话，常规切换数据库会把里面所有的表遍历一遍，会很慢甚至是卡死。

解决方法： 登录的时候直接在最后面加一个 -A 就行了。

[root@localhost ~]# "/usr/local/mysql-8.0.11/bin/mysql" -uroot -p123456 -A

实战演示： 我演示的数据库就是一个数据量很大的数据库，切换数据库时半天也没有好。

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| ncc_0807auto       |
| ncc_0807mysql      |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.00 sec)

mysql> use ncc_0807mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

加上参数后可以看到直接就切换成功了。

[root@localhost ~]# "/usr/local/mysql-8.0.11/bin/mysql" -uroot -p123456 -A
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 41
Server version: 8.0.11 MySQL Community Server - GPL

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| ncc_0807auto       |
| ncc_0807mysql      |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.01 sec)

mysql> use ncc_0807mysql;
Database changed
mysql>