MySQL's default database

Understanding of MySQL

 

What are the default databases:

1. information_schema

2. mysql

3. test

4. ewsdoa_schema

5. performance_schema

 

 

information_schema

 

Save the information of all databases of MySQl service.

How many databases does the MySQL service have, what tables are in each database, what data types are the fields in each table, what indexes are in each table, and what permissions do each database need to access.

 

 

mysql

 

Saves MySQL permissions, parameters, objects, and status information.

Such as which users can access this data, DB parameters, plug-ins, master-slave

 

 

performance_schema

 

Mainly used to collect database server performance parameters

1. Provide detailed information about process waiting, including locks, mutex variables, and file information;
2. Save historical event summary information and make detailed judgments for providing MySQL server performance;
3. It is very easy to add and delete monitoring event points, and you can change the monitoring cycle of the mysql server at will, for example (CYCLE, MICROSECOND)

 

test

 

nothing