


The differences between the four acceleration and cache extensions in PHP: eAccelerator, memcached, xcache, and APC
This article mainly introduces the differences and selection suggestions of four acceleration and cache extensions in PHP, such as eAccelerator, memcached, xcache, and APC. Friends in need can refer to it
Friends who are tossing VPS, after installing LNMP and other web operating environments Finally, some cache extensions will be installed to improve the running speed of PHP. The cache extensions that are often introduced include eAccelerator, memcached, xcache, and Alternative PHP Cache. What are the differences between them? What are their respective functions? How do we do it? Choice? This is the answer given to you in this article.
1. eAccelerator
eAccelerator is a free and open source PHP accelerator that optimizes and dynamic content caching, improves the caching performance of PHP scripts, and almost completely eliminates the server overhead of PHP scripts in the compiled state. It also optimizes scripts to speed up their execution efficiency. Improve PHP program code execution efficiency by 1-10 times. It can be understood from the text: eAccelerator is a PHP accelerator extension.
2. memcached
Memcached is a high-performance distributed memory object caching system used in dynamic web applications to reduce database load. It delivers the speed of dynamic, database-driven websites by caching data and objects in memory to reduce the number of database reads. From the text, it can be understood as: memory cache extension, and it is mostly used for cluster servers. It is mainly used for distributed cache and is regarded as database cache.
3. Alternative PHP Cache (APC cache)
Alternative PHP Cache (APC cache) is an open source cache tool effective for PHP. It can cache the PHP intermediate code of Opcode (object file). APC's cache is divided into two parts: system cache and user data cache. The system cache is used automatically. It means that APC caches the compilation results of the PHP file source code, and then compares the time stamp when calling again. If not expired, the cached code is used to run. The default cache is 3600s (one hour). However, this still wastes a lot of CPU time. Therefore, you can set the system cache in php.ini to never expire (apc.ttl=0). However, if it is set like this, it will be required after running the PHP code. Restart your web server (such as apache...). The current performance test of APC generally refers to this layer of cache; from the literal meaning: Alternative PHP Cache (APC cache) can also be regarded as a memory cache extension, which can be regarded as a database Cache extension.
4. Xcache
is an open source opcode cache/optimizer. It can improve the performance of PHP on the server. It buffers the compiled PHP data into shared memory to avoid repeated compilation processes. The buffer can be used directly Zone compiled code to increase speed. Typically increases your page generation rate by 2 to 5 times, reducing server load. In fact, it is a PHP accelerator extension like eAccelerator.
The above are their functions and differences. To put it simply: eAccelerator and xcache are PHP cache extensions, while memcached and APC cache are database cache extensions. Generally, you only need to install one of them, don’t be greedy for too much. In addition, actual testing found that when the number of caches exceeds a certain threshold, APC's performance is not as good as Memcache. Therefore, when it comes to the choice of extensions, I usually choose the combination of xcache+memcached.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

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.


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