php的垃圾收集机制是怎样的?解决方案
php的垃圾收集机制是怎样的?
如题...
是网上搜得tencent笔试题...
------解决方案--------------------
只知道session的垃圾收集机制
------解决方案--------------------
不懂，帮顶,期待高手.
------解决方案--------------------
其他的手册上说,主要是资源会产后垃圾问题,但PHP4后已有记数功能,哪果资源没有被占用,会自动释放
------解决方案--------------------
在PHP中，没有任何变量指向这个对象时，这个对象就成为垃圾。PHP会将其在内存中销毁；这是PHP 的GC垃圾处理机制，防止内存溢出。
当一个 PHP线程结束时，当前占用的所有内存空间都会被销毁，当前程序中所有对象同时被销毁。GC进程一般都跟着每起一个SESSION而开始运行的.gc目的是为了在session文件过期以后自动销毁删除这些文件.
------解决方案--------------------
执行这些函数也可以起到回收作用
__destruct /unset/mysql_close
------解决方案--------------------
php的垃圾回收机制并不需要程序员考虑，
只要对不用的resource及时的关闭，对占用资源大的变量及时unset就可以了。
------解决方案--------------------
php对session有明确的gc处理时间设定
session.gc_maxlifetime
------解决方案--------------------
个人觉得每个请求是一个进程吧
------解决方案--------------------
我留个痕迹
------解决方案--------------------
------解决方案--------------------
------解决方案--------------------
对于内存占用的垃圾处理吗？
首先ＰＨＰ作为脚本语言是页面结束即释放变量所占内存的。
如果说有垃圾，那就是整体的程序在框架使用中，会多次调用同一文件等等造成的非单件模式等。
所以在出来的时候，必要的用_once 引用，在声明类的时候使用单件模式。还有简化逻辑等等。
而如果妄想让PHP自己本身管理内存，进行垃圾管理。呵呵。好像PHP还办不到，对于析构函数，ANDI在他的书里写的很明白。可有可无，不可置否。
而内存管理的东西一般都是桌面程序更多去考虑的。PHP还非要搞一个内存管理的东西，哎，鞭长莫及吧。
------解决方案--------------------
学习
------解决方案--------------------
呵呵~~，学习拉！
------解决方案--------------------
不懂，看过JavaScript的垃圾回收机制，PHP还真没注意过！
------解决方案--------------------
记得书上说用引用计数和写时复制来管理内存，也是PHP的内存管理的主要机制
------解决方案--------------------
中国的招聘总是整那么多的名词，那么多的理论，开发的时候还要看具体的能力的
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
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1382
52
PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian
Dec 24, 2024 pm 04:42 PM
PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati
How To Set Up Visual Studio Code (VS Code) for PHP Development
Dec 20, 2024 am 11:31 AM
Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c
7 PHP Functions I Regret I Didn't Know Before
Nov 13, 2024 am 09:42 AM
If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op
How do you parse and process HTML/XML in PHP?
Feb 07, 2025 am 11:57 AM
This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
PHP Program to Count Vowels in a String
Feb 07, 2025 pm 12:12 PM
A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
