MySQL is one of the most widely used open source database management systems in the world. It can handle the storage, reading and writing of large data, and also has the characteristics of high availability, high security and high performance. MySQL's architecture is very delicate and consists of many modules, from physical storage engine, query optimizer, transaction support, replication, partitioning to security, monitoring, etc., which makes MySQL have good scalability and flexibility. This article will start from a beginner's perspective, gain an in-depth understanding of the MySQL architecture, and help readers better master the MySQL database.
MySQL's logical structure mainly consists of three parts: client, middleware and server.
(1) Client
MySQL client is the interface for applications to interact with the MySQL database, mainly including command line clients, GUI tools and APIs. The most commonly used one is the command line client. By entering commands in the terminal window, you can connect to the MySQL instance and execute SQL statements.
(2) Middleware
The main function of MySQL middleware is to provide connection pooling, load balancing, fault handling and caching. Common middleware include MySQL Proxy, MaxScale, etc. The existence of middleware can effectively improve the high availability and performance of MySQL.
(3) Server side
MySQL server side includes components such as connection manager, query processor, storage engine, plug-in, replication, cache manager and log manager.
The physical architecture of MySQL refers to the storage structure of the database on the disk, including components such as data files, log files, and index files.
(1) Data files
MySQL data files mainly store data structures such as tables and indexes, including three types of files: table space files, table files and index files. Tablespace files are used to store all table and index-related data, and are usually files used by the InnoDB storage engine.
(2) Log files
MySQL’s log files mainly include error logs, binary logs and slow query logs. The error log records any errors or warning information during the startup, running and shutdown process of MySQL; the binary log is used to record all SQL operations that change MySQL data so that the operations can be copied to other MySQL instances; the slow query log is used for Log queries whose execution time exceeds a certain threshold.
(3) Index files
MySQL’s index files mainly serve the InnoDB storage engine. They store primary key indexes, auxiliary indexes, full-text indexes, etc.
MySQL storage engine is the software used to manage data. They determine how MySQL stores, retrieves and processes data. MySQL supports a variety of storage engines, among which common ones are InnoDB, MyISAM, Memory and CSV.
(1)InnoDB
InnoDB storage engine is the default storage engine of MySQL. It is a transaction-safe storage engine that supports high concurrency and read and write performance, and has row-level locking and multi-version. Features such as concurrency control and crash recovery.
(2)MyISAM
MyISAM storage engine is one of the earliest storage engines of MySQL. It is a non-transactionally secure storage engine with high performance and simple data model and is widely used. For web applications, data warehouses and reports, etc.
(3)Memory
Memory storage engine is a memory storage engine of MySQL. It stores all data in memory and provides very fast data access and update performance, but it does not Support persistent data.
(4)CSV
CSV storage engine is an engine of MySQL used to store CSV files. The data is stored in the file in comma-separated form. It is widely used for data exchange and Data backup and other scenarios.
MySQL query optimizer is the core module used to optimize the SQL query process. It dynamically analyzes SQL query statements and their execution. Plan, and then select the optimal execution plan for execution, thereby improving MySQL query performance. The query optimizer uses various techniques and strategies, such as execution plan space exploration, complexity estimation, and statistical information, to generate optimal execution plans and arrange execution sequences and methods for the execution plans.
MySQL fault handling and replication are important components of MySQL high availability. MySQL provides a variety of fault handling and replication mechanisms, including master-slave replication, synchronous replication, multi-master replication, GTID, etc. These mechanisms can help administrators easily manage MySQL clusters and improve MySQL availability and performance.
MySQL security management is an important part of MySQL, and it should be given full attention. MySQL provides a variety of security measures, including access control, encrypted communication, auditing, and data desensitization. Administrators can configure MySQL security policies according to needs to ensure the security and integrity of MySQL.
In short, MySQL is a very powerful and flexible relational database with a complete architecture that can cope with the data management needs of various scenarios. As a beginner, it is very necessary to understand the architecture and core modules of MySQL. Mastering this knowledge can help us better manage and optimize the MySQL database.
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