MySQL eight shares

1. towards MySQL When sending a request ,MySQL What has been done

From the perspective of database architecture ：

1. adjoining course
   1） Authorized certification ： Before the real operation , You also need to call the user module to check the authorization , To verify whether the user has permission . After the adoption of , Connection thread on
   Start receiving and processing requests from clients .
   The functions realized by the user module , It mainly includes user login connection permission control and user authorization management . It's like MySQL Like the gate guard , "
   Decide whether to give it to visitors “ Open door ”.
   stay MySQL in , Divide client requests into two types ： One is query（SQL sentence ）, Need to call Parser（ Query parser ） To be able to
   Request to execute ; One is command（ command ）, No call required Parser Requests that can be executed directly .
   2） Connection processing ： The client and the database service layer are established through the connection management module TCP Connect , And request a connection thread .
   If there are idle connection threads in the connection pool , Is assigned to this connection , without , Without exceeding the maximum number of connections , Create a new connection thread to take charge of the client .
   The connection management module is responsible for listening to MySQL Server All kinds of requests , Receive connection request , Forward all connection requests to thread management module .
   Every connection on MySQL Server All client requests will be assigned （ Or create ） A connection thread serves it alone .
   And the main job of the connection thread is to be responsible for MySQL Server Communication with clients , To receive commands from the client, please