MySQL table read lock

 Add the same read lock to the table session Can read the locking table , But you can't read other tables , You can't write locking tables and other tables .
                   Different locks session You can read locked tables and other tables , Writing other tables can succeed, but writing locked tables will block , Wait for the lock to release before operation 
1、session1: lock table mylock read; --  to mylock Read lock on the meter 
2、session1: select * from mylock; --  You can query 
3、session1：select * from tdep; -- Cannot access non locked table 
4、session2   ：select * from mylock; --  You can query   There is no lock 
5、session2：update mylock set name='x' where id=2; --  Modify blocking , Automatically add line write lock 
6、session1：unlock tables; --  Release the watch lock 
7、session2：Rows matched: 1 Changed: 1 Warnings: 0 --  Modification execution complete 
8、session1：select * from tdep; -- You can visit