use database 很慢/You can turn off this feature to get a quicker startup with –A

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

当切换到某个库时，经常会出现上面信息，意思是预读这个库中表以及表列信息。

但是当库中表很多，表中数据很大时，就会出现执行use <库名>后半天没反应，连接很慢的情况

解决办法：

上面其实已经有提示了（You can turn off this feature to get a quicker startup with -A）

就是在登陆连接mysql时使用-A参数，这样就不会预读库中表信息了，能提高连接库的速度.

shell> mysql -h hostname -u username -P port -p -A

Enter password:

MySQL -A参数含义：

shell> mysql --help

-A, --no-auto-rehash

No automatic rehashing. One has to use 'rehash' to get table and field completion.

This gives a quicker start of mysql and disables rehashing on reconnect.

例子：

shell> mysql -h 127.0.0.1 -u root -P 3306 -p

Enter password:

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

mysql> exit

Bye

shell> mysql -h 127.0.0.1 -u root -P 3306 -p

Enter password:

mysql> use information_schema;

Database changed