How to use caching strategies to reduce the memory footprint of PHP programs?

How to use caching strategies to reduce the memory usage of PHP programs?

Abstract: When developing PHP programs, we often encounter the problem of excessive memory usage. In order to solve this problem, we can use caching strategies to reduce the memory footprint of PHP programs. This article will introduce how to use caching strategies to optimize PHP programs and give corresponding code examples.

1. Why you need to use caching strategy

In PHP, every time a page is requested, the server will re-execute the PHP script to generate the page content. This means that each request results in a PHP script being parsed and executed. This process is very memory intensive. When concurrent requests increase, the memory usage of the server will also increase sharply, resulting in server performance degradation.

The caching strategy can save some commonly used page content in memory and directly return the cached content on the next request, avoiding repeated PHP script parsing and execution processes, thereby reducing memory usage.

2. How to use caching strategy

1. Page caching

Page caching is one of the most common caching strategies. When a page has relatively stable content and does not change with changes in user requests, the page content can be cached and the cached content can be returned directly on the next request without regenerating the page.

The specific implementation code is as follows:

<?php
function getPageContent($pageId) {
  $cacheKey = 'page_' . $pageId;
  $content = getFromCache($cacheKey); // 从缓存中获取页面内容

  if (!$content) {
    $content = generatePageContent($pageId); // 生成页面内容
    saveToCache($cacheKey, $content); // 将页面内容保存到缓存
  }

  return $content;
}
?>

2. Data cache

In addition to page caching, some frequently read data can also be saved in the cache , reduce the number of database accesses, thereby reducing memory usage.

The specific implementation code is as follows:

<?php
function getUserInfo($userId) {
  $cacheKey = 'user_' . $userId;
  $userInfo = getFromCache($cacheKey); // 从缓存中获取用户信息

  if (!$userInfo) {
    $userInfo = getUserInfoFromDB($userId); // 从数据库中获取用户信息
    saveToCache($cacheKey, $userInfo); // 将用户信息保存到缓存
  }

  return $userInfo;
}
?>

3. Code caching

In addition to page and data caching, code caching can also be used to improve the performance of PHP scripts Execution speed. The compilation and execution of PHP code is time-consuming. By caching the compiled PHP script and directly using the cached code on the next request, the execution efficiency of the PHP script can be greatly improved.

Enable the opcache extension in the PHP configuration file to implement code caching:

opcache.enable=1
opcache.enable_cli=1
opcache.memory_consumption=128
opcache.interned_strings_buffer=8
opcache.max_accelerated_files=4000
opcache.fast_shutdown=1

3. Summary

The memory usage of the PHP program can be effectively reduced by using caching strategies. Improve server performance. This article introduces the implementation methods of page caching, data caching and code caching, and gives corresponding code examples. In the actual development process, an appropriate caching strategy can be selected according to specific circumstances to meet the needs of the project.

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