Function and usage of clean_post_cache() in wordpress

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    2024-01-05T16:26:05+00:00

    The clean_post_cache() function in WordPress is used to remove a post and its associated data from the WordPress object cache. This function is particularly useful when you want to ensure that your WordPress site is serving the most up-to-date version of a post.

    Here's a detailed explanation:

    Function Signature

    clean_post_cache( int|WP_Post $post )
    

    Description

    • Purpose: clean_post_cache() is designed to clear or 'clean' the cache for a specific post. When a post is cached, WordPress stores a copy of its data (like the post content, metadata, and terms) in memory to improve website performance by reducing database queries. However, if the post is updated, the cache might still hold the old version of the post. This function ensures that the cached data is deleted, and subsequent requests for the post will fetch the latest data from the database.
    • Cache Cleaning: It involves deleting the cached data of the post. This includes the post itself, any associated metadata, and terms linked to the post.
    • Term Object Cache: The function also cleans the term object cache associated with the post. Terms usually refer to categories and tags in WordPress.
    • Cache Invalidation Suspension: The function checks the global variable $_wp_suspend_cache_invalidation. If this variable is set (not empty), the cache cleaning operation will not be executed. This global variable is managed by the wp_suspend_cache_invalidation() function, which temporarily suspends cache invalidation for performance reasons during certain bulk operations.

    Parameters

    • $post (int|WP_Post) (Required): This parameter accepts either a post ID (integer) or a post object (WP_Post). It specifies the post for which the cache should be cleaned.

    Usage Example

    $post_id = 123; // Assume this is the ID of the post to clean from cache
    clean_post_cache( $post_id );
    
    // Alternatively, using a WP_Post object
    $post = get_post( $post_id );
    clean_post_cache( $post );
    

    In these examples, the clean_post_cache() function is called with either a post ID or a WP_Post object. This action will remove all cached data related to the specified post, ensuring that any future requests for this post will be served with the most current data from the database.

    Important Considerations

    • When to Use: It's generally used in scenarios where post data is updated programmatically or via actions where cache invalidation might not occur automatically.
    • Performance Impact: Use this function judiciously, as clearing the cache frequently can negatively impact site performance, especially on high-traffic websites.

    This function is a part of WordPress's extensive system for managing and optimizing the performance of database queries through object caching. It's a powerful tool for developers looking to maintain control over the data consistency and performance of WordPress sites.

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