小tip1
mysql> use test
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
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.