解决Reading table information for completion of table and column names You ca...

jiawang

OS：centos7.8
db：MySQL8.11


mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.04 sec)


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

Database changed

加载表和列名称完成的表信息
您可以关闭此功能，以获得更快的启动使用option：-A 就是不预读数据库的信息就ok了

出现问题的原因是::
我们进入mysql 时，没有使用-A参数；
即我们使用
mysql -hhostname -uusername -ppassword -Pport 的方式进入数据，
而没有使用
mysql -hhostname -uusername -ppassword -Pport -A的方式进入数据库。


解决方式一：
[mysql@strong bin]$ ./mysql -uroot -p -A
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 13
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> use information_schema
Database changed

解决方式二：
先查看当前的进程情况,:
mysql> show processlist ;
+----+-----------------+-----------+--------------------+---------+------+------------------------+------------------+
| Id | User            | Host      | db                 | Command | Time | State                  | Info             |
+----+-----------------+-----------+--------------------+---------+------+------------------------+------------------+
|  4 | event_scheduler | localhost | NULL               | Daemon  | 2186 | Waiting on empty queue | NULL             |
|  9 | root            | localhost | information_schema | Query   |    0 | starting               | show processlist |
+----+-----------------+-----------+--------------------+---------+------+------------------------+------------------+
2 rows in set (0.00 sec)


如果进程中有锁表的，比如id为4,则可以使用kill命令,结束它.
mysql> kill 4;

mysql> use information_schema
Database changed