亚洲国产日韩欧美一区二区三区,精品亚洲国产成人av在线,国产99视频精品免视看7,99国产精品久久久久久久成人热,欧美日韩亚洲国产综合乱

Table of Contents
1. Use the correct index
2. Avoid choosing*
5. Avoid subqueries; use connection instead
6. Use query cache
7. Partition the large table
Home Database Mysql Tutorial Query optimization in MySQL is essential for improving database performance, especially when dealing with large data sets

Query optimization in MySQL is essential for improving database performance, especially when dealing with large data sets

Apr 08, 2025 pm 07:12 PM
mysql

Query optimization in MySQL is essential for improving database performance, especially when dealing with large data sets

1. Use the correct index

  • Index speeds up data retrieval by reducing the amount of data scanned
 select * from employees where last_name = 'smith';
  • If you look up a column in a table multiple times, create an index for that column

  • Create a composite index if you or your app needs data from multiple columns based on the criteria

2. Avoid choosing*

  • Select only those columns you need, if you select all the columns you don't need, this will only consume more server memory and cause the server to slow down at high load or frequency times

For example, your table contains columns like created_at and updated_at and timestamps, and then avoid selecting * because they are not required under normal circumstances

Inefficient query

 select * from orders where order_date > '2023-01-01';

Optimize query

 select order_id, customer_id from orders where order_date > '2023-01-01';

  1. Optimize connections
  • Make sure that the index exists on the columns used in the join condition.

If you use primary key to join the table, you don't need to create it because the primary key is already an index

 select orders.order_id, customers.name from orders
join customers on orders.customer_id = customers.id
where customers.country = 'usa';

In the above query, orders.customer_id needs to be indexed and its relationship with another table

customers.id is the primary key of the customers table, so there is no need to create an index

customers.country needs to be indexed because it is a conditional

5. Avoid subqueries; use connection instead

6. Use query cache

  • If your query results do not change frequently, use mysql's query cache.

For example, user and order lists and other infrequently changed content

7. Partition the large table

 CREATE TABLE orders (
    order_id INT NOT NULL,
    order_date DATE NOT NULL,
    ...
    PRIMARY KEY (order_id, order_date)
)
PARTITION BY RANGE (YEAR(order_date)) (
    PARTITION p0 VALUES LESS THAN (2000),
    PARTITION p1 VALUES LESS THAN (2010),
    PARTITION p2 VALUES LESS THAN (2020),
    PARTITION p3 VALUES LESS THAN MAXVALUE
);

The above is the detailed content of Query optimization in MySQL is essential for improving database performance, especially when dealing with large data sets. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

PHP Tutorial
1488
72
How to use PHP to develop a Q&A community platform Detailed explanation of PHP interactive community monetization model How to use PHP to develop a Q&A community platform Detailed explanation of PHP interactive community monetization model Jul 23, 2025 pm 07:21 PM

1. The first choice for the Laravel MySQL Vue/React combination in the PHP development question and answer community is the first choice for Laravel MySQL Vue/React combination, due to its maturity in the ecosystem and high development efficiency; 2. High performance requires dependence on cache (Redis), database optimization, CDN and asynchronous queues; 3. Security must be done with input filtering, CSRF protection, HTTPS, password encryption and permission control; 4. Money optional advertising, member subscription, rewards, commissions, knowledge payment and other models, the core is to match community tone and user needs.

How to set environment variables in PHP environment Description of adding PHP running environment variables How to set environment variables in PHP environment Description of adding PHP running environment variables Jul 25, 2025 pm 08:33 PM

There are three main ways to set environment variables in PHP: 1. Global configuration through php.ini; 2. Passed through a web server (such as SetEnv of Apache or fastcgi_param of Nginx); 3. Use putenv() function in PHP scripts. Among them, php.ini is suitable for global and infrequently changing configurations, web server configuration is suitable for scenarios that need to be isolated, and putenv() is suitable for temporary variables. Persistence policies include configuration files (such as php.ini or web server configuration), .env files are loaded with dotenv library, and dynamic injection of variables in CI/CD processes. Security management sensitive information should be avoided hard-coded, and it is recommended to use.en

Automating MySQL Deployments with Infrastructure as Code Automating MySQL Deployments with Infrastructure as Code Jul 20, 2025 am 01:49 AM

To achieve MySQL deployment automation, the key is to use Terraform to define resources, Ansible management configuration, Git for version control, and strengthen security and permission management. 1. Use Terraform to define MySQL instances, such as the version, type, access control and other resource attributes of AWSRDS; 2. Use AnsiblePlaybook to realize detailed configurations such as database user creation, permission settings, etc.; 3. All configuration files are included in Git management, support change tracking and collaborative development; 4. Avoid hard-coded sensitive information, use Vault or AnsibleVault to manage passwords, and set access control and minimum permission principles.

How to use PHP to develop product recommendation module PHP recommendation algorithm and user behavior analysis How to use PHP to develop product recommendation module PHP recommendation algorithm and user behavior analysis Jul 23, 2025 pm 07:00 PM

To collect user behavior data, you need to record browsing, search, purchase and other information into the database through PHP, and clean and analyze it to explore interest preferences; 2. The selection of recommendation algorithms should be determined based on data characteristics: based on content, collaborative filtering, rules or mixed recommendations; 3. Collaborative filtering can be implemented in PHP to calculate user cosine similarity, select K nearest neighbors, weighted prediction scores and recommend high-scoring products; 4. Performance evaluation uses accuracy, recall, F1 value and CTR, conversion rate and verify the effect through A/B tests; 5. Cold start problems can be alleviated through product attributes, user registration information, popular recommendations and expert evaluations; 6. Performance optimization methods include cached recommendation results, asynchronous processing, distributed computing and SQL query optimization, thereby improving recommendation efficiency and user experience.

How to build an online customer service robot with PHP. PHP intelligent customer service implementation technology How to build an online customer service robot with PHP. PHP intelligent customer service implementation technology Jul 25, 2025 pm 06:57 PM

PHP plays the role of connector and brain center in intelligent customer service, responsible for connecting front-end input, database storage and external AI services; 2. When implementing it, it is necessary to build a multi-layer architecture: the front-end receives user messages, the PHP back-end preprocesses and routes requests, first matches the local knowledge base, and misses, call external AI services such as OpenAI or Dialogflow to obtain intelligent reply; 3. Session management is written to MySQL and other databases by PHP to ensure context continuity; 4. Integrated AI services need to use Guzzle to send HTTP requests, safely store APIKeys, and do a good job of error handling and response analysis; 5. Database design must include sessions, messages, knowledge bases, and user tables, reasonably build indexes, ensure security and performance, and support robot memory

mysql revoke privileges from user mysql revoke privileges from user Jul 16, 2025 am 03:56 AM

To recycle MySQL user permissions using REVOKE, you need to specify the permission type, database, and user by format. 1. Use REVOKEALLPRIVILEGES, GRANTOPTIONFROM'username'@'hostname'; 2. Use REVOKEALLPRIVILEGESONmydb.FROM'username'@'hostname'; 3. Use REVOKEALLPRIVILEGESONmydb.FROM'username'@'hostname'; 3. Use REVOKE permission type ON.*FROM'username'@'hostname'; Note that after execution, it is recommended to refresh the permissions. The scope of the permissions must be consistent with the authorization time, and non-existent permissions cannot be recycled.

How to develop AI intelligent form system with PHP PHP intelligent form design and analysis How to develop AI intelligent form system with PHP PHP intelligent form design and analysis Jul 25, 2025 pm 05:54 PM

When choosing a suitable PHP framework, you need to consider comprehensively according to project needs: Laravel is suitable for rapid development and provides EloquentORM and Blade template engines, which are convenient for database operation and dynamic form rendering; Symfony is more flexible and suitable for complex systems; CodeIgniter is lightweight and suitable for simple applications with high performance requirements. 2. To ensure the accuracy of AI models, we need to start with high-quality data training, reasonable selection of evaluation indicators (such as accuracy, recall, F1 value), regular performance evaluation and model tuning, and ensure code quality through unit testing and integration testing, while continuously monitoring the input data to prevent data drift. 3. Many measures are required to protect user privacy: encrypt and store sensitive data (such as AES

Securing MySQL Connections with SSL/TLS Encryption Securing MySQL Connections with SSL/TLS Encryption Jul 21, 2025 am 02:08 AM

Why do I need SSL/TLS encryption MySQL connection? Because unencrypted connections may cause sensitive data to be intercepted, enabling SSL/TLS can prevent man-in-the-middle attacks and meet compliance requirements; 2. How to configure SSL/TLS for MySQL? You need to generate a certificate and a private key, modify the configuration file to specify the ssl-ca, ssl-cert and ssl-key paths and restart the service; 3. How to force SSL when the client connects? Implemented by specifying REQUIRESSL or REQUIREX509 when creating a user; 4. Details that are easily overlooked in SSL configuration include certificate path permissions, certificate expiration issues, and client configuration requirements.

See all articles