To roll back the WordPress version, you can use the plug-in or manually replace the core file and disable automatic updates. 1. Use WPDowngrade and other plug-ins to enter the target version number to automatically download and replace; 2. Manually download the old version of WordPress and replace wp-includes, wp-admin and other files through FTP, but retain wp-config.php and wp-content; 3. Add code in wp-config.php or use filters to disable core automatic updates to prevent further upgrades. Be sure to back up the website and database before operation to ensure safety and reliability. It is recommended to keep the latest version for security and functional support in the long term.

The steps to create a custom shortcode in WordPress are as follows: 1. Write a PHP function through functions.php file or custom plug-in; 2. Use add_shortcode() to bind the function to the shortcode tag; 3. Process parameters in the function and return the output content. For example, when creating button shortcodes, you can define color and link parameters for flexible configuration. When using it, you can insert a tag like [buttoncolor="red"url="https://example.com"] in the editor, and you can use do_shortcode() to model it

The main reasons why WordPress causes the surge in server CPU usage include plug-in problems, inefficient database query, poor quality of theme code, or surge in traffic. 1. First, confirm whether it is a high load caused by WordPress through top, htop or control panel tools; 2. Enter troubleshooting mode to gradually enable plug-ins to troubleshoot performance bottlenecks, use QueryMonitor to analyze the plug-in execution and delete or replace inefficient plug-ins; 3. Install cache plug-ins, clean up redundant data, analyze slow query logs to optimize the database; 4. Check whether the topic has problems such as overloading content, complex queries, or lack of caching mechanisms. It is recommended to use standard topic tests to compare and optimize the code logic. Follow the above steps to check and solve the location and solve the problem one by one.

Methods to optimize WordPress sites that do not rely on plug-ins include: 1. Use lightweight themes, such as Astra or GeneratePress, to avoid pile-up themes; 2. Manually compress and merge CSS and JS files to reduce HTTP requests; 3. Optimize images before uploading, use WebP format and control file size; 4. Configure.htaccess to enable browser cache, and connect to CDN to improve static resource loading speed; 5. Limit article revisions and regularly clean database redundant data.

Miniving JavaScript files can improve WordPress website loading speed by removing blanks, comments, and useless code. 1. Use cache plug-ins that support merge compression, such as W3TotalCache, enable and select compression mode in the "Minify" option; 2. Use a dedicated compression plug-in such as FastVelocityMinify to provide more granular control; 3. Manually compress JS files and upload them through FTP, suitable for users familiar with development tools. Note that some themes or plug-in scripts may conflict with the compression function, and you need to thoroughly test the website functions after activation.

TransientsAPI is a built-in tool in WordPress for temporarily storing automatic expiration data. Its core functions are set_transient, get_transient and delete_transient. Compared with OptionsAPI, transients supports setting time of survival (TTL), which is suitable for scenarios such as cache API request results and complex computing data. When using it, you need to pay attention to the uniqueness of key naming and namespace, cache "lazy deletion" mechanism, and the issue that may not last in the object cache environment. Typical application scenarios include reducing external request frequency, controlling code execution rhythm, and improving page loading performance.

Object cache assists persistent storage, suitable for high access and low updates, tolerating short-term lost data. 1. Data suitable for "persistence" in cache includes user configuration, popular product information, etc., which can be restored from the database but can be accelerated by using cache. 2. Select a cache backend that supports persistence such as Redis, enable RDB or AOF mode, and configure a reasonable expiration policy, but it cannot replace the main database. 3. Set long TTL or never expired keys, adopt clear key name structure such as user:1001:profile, and update the cache synchronously when modifying data. 4. It can combine local and distributed caches to store small data locally and big data Redis to store big data and use it for recovery after restart, while paying attention to consistency and resource usage issues.

PluginCheck is a tool that helps WordPress users quickly check plug-in compatibility and performance. It is mainly used to identify whether the currently installed plug-in has problems such as incompatible with the latest version of WordPress, security vulnerabilities, etc. 1. How to start the check? After installation and activation, click the "RunaScan" button in the background to automatically scan all plug-ins; 2. The report contains the plug-in name, detection type, problem description and solution suggestions, which facilitates priority handling of serious problems; 3. It is recommended to run inspections before updating WordPress, when website abnormalities are abnormal, or regularly run to discover hidden dangers in advance and avoid major problems in the future.