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


當切換到某個庫時，經常會出現上面資訊，意思是預讀這個庫中表以及表列資訊。

但是當庫中表很多，表中資料很大時，就會出現執行use <庫名>後半天沒反應，連線很慢的情況

 

解決辦法：

上面其實已經有提示了（You can turn off this feature to get a quicker startup with -A）

就是在登陸連線mysql時使用-A引數，這樣就不會預讀庫中表資訊了，能提高連線庫的速度.

 

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

Enter password:

MySQL -A引數含義：

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