How to control cache expiration time in PHP?
With the popularity of Internet applications, website response speed has become more and more of a focus for users. In order to quickly respond to user requests, websites often use caching technology to cache data, thereby reducing the number of database queries. However, cache expiration time has an important impact on response speed. This article will discuss methods of controlling cache expiration time to help PHP developers better apply caching technology.
1. What is cache expiration time?
The cache expiration time refers to the time when the data in the cache is considered to have expired. It determines when the data in the cache needs to be updated. In most cases, the data in the cache should expire after a certain period of time to ensure that the data in the cache remains in sync with the source data.
2. Why should we control the cache expiration time?
The purpose of controlling the cache expiration time is to ensure that the data in the cache does not become outdated, thereby ensuring the website response speed. Expired cached data may cause a decrease in cache hit rate and increase the load on the server.
3. Methods to control cache expiration time
1. Set expiration time
When using memcache cache, you can control the cache expiration time by setting the expiration time. For example:
$key = 'user:1'; $val = $memcache->get($key); if ($val === false) { $val = db_query('SELECT * FROM user WHERE id = ?', $id); $memcache->set($key, $val, MEMCACHE_COMPRESSED, 3600); //设置过期时间为3600秒 }
In this code, the fourth parameter of the memcache->set() function indicates the validity period of the cached data, in seconds.
2. Use automatic expiration cache
Automatic expiration cache means that when the cached data expires, the cache is automatically updated from the source data. This method requires setting a cache automatic expiration time when using cache. When the cache time expires, the cache will be automatically updated from the source data at the next cache request. For example:
$key = 'user:1'; $val = apc_fetch($key, $success); if (!$success) { $val = db_query('SELECT * FROM user WHERE id = ?', $id); apc_add($key, $val, 3600); //设置过期时间为3600秒 }
In this code, after the apc_add() function sets the cache time, after the cache expires, if the cache no longer exists, the cache will be automatically updated from the source data.
3. Use OPcache
OPcache is an extension of PHP that can cache compiled PHP scripts. After OPcache is enabled, PHP scripts will only be compiled and interpreted once, and the compiled results are cached in memory, thus improving the execution efficiency of PHP code. The cache expiration time of OPcache is determined by the parameters in the OPcache configuration file. For example:
[opcache] opcache.enable=1 opcache.enable_cli=0 opcache.memory_consumption=128 opcache.interned_strings_buffer=8 opcache.max_accelerated_files=4000 opcache.revalidate_freq=60 opcache.fast_shutdown=1 opcache.enable_file_override=0
The opcache.revalidate_freq parameter in this configuration file indicates how long the cached data needs to be re-validated, and determines the cache expiration time of OPcache.
4. Summary
Controlling cache expiration time is one of the skills that PHP developers must master. In actual applications, developers need to choose appropriate caching technology and select an appropriate cache expiration time based on application scenarios and requirements. At the same time, it is also necessary to clean and update the cached data of the application regularly. By rationally using caching technology and controlling cache expiration time, we can improve the response speed of the website and improve the user experience.
The above is the detailed content of How to control cache expiration time in PHP?. For more information, please follow other related articles on the PHP Chinese website!

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

Key players in HTTP cache headers include Cache-Control, ETag, and Last-Modified. 1.Cache-Control is used to control caching policies. Example: Cache-Control:max-age=3600,public. 2. ETag verifies resource changes through unique identifiers, example: ETag: "686897696a7c876b7e". 3.Last-Modified indicates the resource's last modification time, example: Last-Modified:Wed,21Oct201507:28:00GMT.

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

Atom editor mac version download
The most popular open source editor

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft