MySQL advanced part 2: MySQL architecture

Whole MySQL Server It consists of

• Connection Pool : Connection pool components
• Management Services & Utilities : Manage service and tool components
• SQL Interface : SQL Interface component
• Parser : Query analyzer component
• Optimizer : Optimizer components
• Caches & Buffers : Buffer pool components
• Pluggable Storage Engines : Storage engine
• File System : file system

1） adjoining course

At the top are some clients and link services , Contains the local sock Communication and most are client based / The implementation of server-side tools is similar to TCP/IP Communication for . Mainly completes some similar to the connection processing 、 Authorized certification 、 And related safety programs . The concept of thread pool is introduced in this layer , Provide threads for clients accessing through authentication security . Also on this layer, we can implement the system based on SSL Security links for . The server will also verify the operation permissions it has for each client of secure access .

2） Service layer

The second layer architecture mainly completes most of the core service functions , Such as SQL Interface , And complete the cache query ,SQL Analysis and optimization of , Execution of some built-in functions . All the cross storage engine functions are also implemented in this layer , Such as The process 、 Functions, etc . On this floor , The server parses the query and creates the corresponding internal parse tree , And it completes the corresponding optimization, such as determining the query order of the table , Whether to use index, etc , Finally, the corresponding execution operation is generated . If it is select sentence , The server also queries the internal cache , If the cache space is large enough , In this way, it can improve the performance of the system in the environment of solving a large number of read operations .

3） Engine layer

Storage engine layer , The storage engine is really responsible for MySQL The storage and extraction of data in , Server pass API Communicating with the storage engine . Different storage engines have different functions , So that we can according to our own needs , To choose the right storage engine .

4） Storage layer

Data storage layer , Mainly store the data on the file system , And complete the interaction with the storage engine .

Compared with other databases ,MySQL It's a little different , Its architecture can be applied in many different scenarios and play a good role . Mainly in the storage engine , Plug in storage engine architecture , Separate query processing from other system tasks and data storage and extraction . This architecture can choose the right storage engine according to the needs of the business and the actual needs .