1.20 System Databases

- mysql: - Stores MySQL user accounts and privilege information, definitions of some stored procedures and events, some log information generated during operation, help information, time zone information, etc. - information_schema: - Stores information about all other databases maintained by the MySQL server, such as tables, views, triggers, columns, and indexes

DatabasesCreated 06/08/2021Updated 06/08/20211 min readhistorical

This is a historical learning note and may contain outdated or incomplete understanding.

mysql:
- It stores MySQL user accounts and privilege information, definitions of some stored procedures and events, some log information generated during operation, help information, time zone information, etc.
information_schema:
- This database stores information about all other databases maintained by the MySQL server, such as what tables, views, triggers, columns, and indexes there are.
- This information is not real user data, but descriptive information, sometimes also called metadata.
performance_schema
- This database mainly stores some state information from the MySQL server during operation and can be regarded as performance monitoring for the MySQL server.
- It includes information such as which statements were executed recently, how much time was spent in each stage of execution, and memory usage.
sys:
- This database mainly combines information_schema and performance_schema through views, allowing programmers to understand some performance information about the MySQL server more conveniently.