With the rapid development of Internet technology and the widespread promotion of applications, a large amount of data is generated and rapidly expanded, which puts forward higher requirements for database storage and query. Among many databases, MySQL is widely used because of its simplicity, ease of use and high performance, especially in PHP development. This article will introduce how to use MySQL 5 and MySQL 8 to optimize database performance and query optimization, and improve the response speed and user experience of the website.

1. MySQL 5 database performance optimization

MySQL 5 is a relational database system with rich functions, high reliability and excellent performance. There are many aspects of MySQL 5 optimization, such as adjusting buffer size, optimizing query statements, index optimization, using partitioned tables, etc.

1. Adjusting Buffer Size

The performance of MySQL 5 depends heavily on the size of its buffer. Therefore, adjusting the buffer size is a very effective optimization method. The buffer can be adjusted by modifying the my.cnf configuration file, as shown below:

[mysqld]

InnoDB cache size

innodb_buffer_pool_size=512M

Maximum number of times to refresh dirty pages

innodb_max_dirty_pages_pct=60

InnoDB log file size

innodb_log_file_size=128M

InnoDB file size

innodb_file_per_table=1

2. Optimize query statements

Query statements are an important part of MySQL 5. Optimizing query statements can improve performance and response speed. Some optimization methods include using SELECT * to replace SELECT field1, field2 and other statements, trying to avoid using subqueries and non-constant functions, using joins instead of subqueries, using foreign keys, etc.

3. Index optimization

Index is an important means of accelerating queries in the database. Optimizing the index can greatly improve query performance. You can use the EXPLAIN command that comes with MySQL to view the execution plan of the query statement and determine whether the index is valid. It is recommended to use a composite index to replace a single index. Generally, a covering index can be created to include all required fields.

4. Use partitioned tables

When the amount of records in a single table is very large, using partitioned tables can significantly improve query speed and maintainability. MySQL 5 supports two partitioning table methods: horizontal and vertical. You can choose the appropriate partitioning method according to the actual situation.

2. MySQL 8 Query Optimization

MySQL 8 is the latest MySQL series database product, with stronger performance, security and scalability. The optimization of MySQL 8 mainly includes the following aspects:

1. Use new index types

MySQL 8 supports more types of index types, such as spatial indexes and hashes Index, PERSISTENT VIRUTAL COLUNM, etc. Using the correct index type can improve query speed and performance.

2. Using analytic functions

MySQL 8 introduces analytic functions, such as RANK, LEAD, LAG, etc. Analytical functions can dynamically calculate and count certain indicators in query results to avoid repeated access to the database in applications. Query performance can be greatly improved using analytic functions.

3. Using full-text index

MySQL 8 introduces a new full-text index function, which can change fields containing text and perform full-text searches on these fields. Full-text index can quickly query relevant keywords and improve search efficiency.

4. Use delayed relational loading

MySQL 8 supports delayed relational loading, which can store relational data directly in JSON format to improve the reading performance of the database. At the same time, delayed relational loading can better support system development in multiple languages ​​and multiple versions, providing help for global applications.

Conclusion

Optimizing database performance and query performance is one of the skills that every developer must master. Through the optimization methods of MySQL 5 and MySQL 8 introduced in this article, PHP developers can have more skills and methods to improve application performance and response speed. It should be noted that optimizing databases and queries requires choosing the most appropriate method according to the specific situation to achieve the best results.

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