Cache: Introduce granular meta-specific last_changed keys to reduce cache over-invalidation

src/wp-includes/class-wp-comment-query.php

@@ -449,7 +449,10 @@ public function get_comments() {
 		unset( $_args['fields'], $_args['update_comment_meta_cache'], $_args['update_comment_post_cache'] );
 
 		$key          = md5( serialize( $_args ) );
-		$last_changed = wp_cache_get_last_changed( 'comment' );
+		$last_changed = (array) wp_cache_get_last_changed( 'comment' );
+		if ( ! empty( $this->meta_query->queries ) ) {
+			$last_changed[] = wp_cache_get_last_changed( 'comment-meta' );
+		}
 
 		$cache_key   = "get_comments:$key";
 		$cache_value = wp_cache_get_salted( $cache_key, 'comment-queries', $last_changed );

src/wp-includes/class-wp-query.php

@@ -3249,6 +3249,9 @@ public function get_posts() {
 		if ( ! empty( $this->tax_query->queries ) ) {
 			$last_changed[] = wp_cache_get_last_changed( 'terms' );
 		}
+		if ( ! empty( $this->meta_query->queries ) ) {
+			$last_changed[] = wp_cache_get_last_changed( 'posts-meta' );
+		}
 
 		if ( $query_vars['cache_results'] && $id_query_is_cacheable ) {
 			$new_request = str_replace( $fields, "{$wpdb->posts}.*", $this->request );

src/wp-includes/class-wp-site-query.php

@@ -355,7 +355,10 @@ public function get_sites() {
 		unset( $_args['fields'], $_args['update_site_cache'], $_args['update_site_meta_cache'] );
 
 		$key          = md5( serialize( $_args ) );
-		$last_changed = wp_cache_get_last_changed( 'sites' );
+		$last_changed = (array) wp_cache_get_last_changed( 'sites' );
+		if ( ! empty( $this->meta_query->queries ) ) {
+			$last_changed[] = wp_cache_get_last_changed( 'sites-meta' );
+		}
 
 		$cache_key   = "get_sites:$key";
 		$cache_value = wp_cache_get_salted( $cache_key, 'site-queries', $last_changed );

src/wp-includes/class-wp-term-query.php

@@ -775,7 +775,10 @@ public function get_terms() {
 
 		if ( $args['cache_results'] ) {
 			$cache_key    = $this->generate_cache_key( $args, $this->request );
-			$last_changed = wp_cache_get_last_changed( 'terms' );
+			$last_changed = (array) wp_cache_get_last_changed( 'terms' );
+			if ( ! empty( $this->meta_query->queries ) ) {
+				$last_changed[] = wp_cache_get_last_changed( 'terms-meta' );
+			}
 			$cache        = wp_cache_get_salted( $cache_key, 'term-queries', $last_changed );
 
 			if ( false !== $cache ) {

src/wp-includes/class-wp-user-query.php

@@ -1071,6 +1071,10 @@ protected function generate_cache_key( array $deprecated, $sql ) {
 	protected function get_cache_last_changed( array $args ) {
 		$last_changed = (array) wp_cache_get_last_changed( 'users' );
 
+		if ( ! empty( $this->meta_query->queries ) ) {
+			$last_changed[] = wp_cache_get_last_changed( 'users-meta' );
+		}
+
 		if ( empty( $args['orderby'] ) ) {
 			// Default order is by 'user_login'.
 			$ordersby = array( 'user_login' => '' );

src/wp-includes/comment.php

@@ -4071,6 +4071,18 @@ function wp_cache_set_comments_last_changed() {
 	wp_cache_set_last_changed( 'comment' );
 }
 
+/**
+ * Sets the last changed time for the 'comment-meta' cache group.
+ *
+ * This is used to invalidate comment query caches that include meta queries,
+ * without affecting query caches for queries that do not use meta.
+ *
+ * @since x.x.x
+ */
+function wp_cache_set_comments_meta_last_changed() {
+	wp_cache_set_last_changed( 'comment-meta' );
+}
+
 /**
  * Updates the comment type for a batch of comments.
  *

src/wp-includes/default-filters.php

@@ -122,22 +122,22 @@
 }
 
 // Post meta.
-add_action( 'added_post_meta', 'wp_cache_set_posts_last_changed' );
-add_action( 'updated_post_meta', 'wp_cache_set_posts_last_changed' );
-add_action( 'deleted_post_meta', 'wp_cache_set_posts_last_changed' );
+add_action( 'added_post_meta', 'wp_cache_set_posts_meta_last_changed' );
+add_action( 'updated_post_meta', 'wp_cache_set_posts_meta_last_changed' );
+add_action( 'deleted_post_meta', 'wp_cache_set_posts_meta_last_changed' );
 
 // User meta.
-add_action( 'added_user_meta', 'wp_cache_set_users_last_changed' );
-add_action( 'updated_user_meta', 'wp_cache_set_users_last_changed' );
-add_action( 'deleted_user_meta', 'wp_cache_set_users_last_changed' );
+add_action( 'added_user_meta', 'wp_cache_set_users_meta_last_changed' );
+add_action( 'updated_user_meta', 'wp_cache_set_users_meta_last_changed' );
+add_action( 'deleted_user_meta', 'wp_cache_set_users_meta_last_changed' );
 add_action( 'add_user_role', 'wp_cache_set_users_last_changed' );
 add_action( 'set_user_role', 'wp_cache_set_users_last_changed' );
 add_action( 'remove_user_role', 'wp_cache_set_users_last_changed' );
 
 // Term meta.
-add_action( 'added_term_meta', 'wp_cache_set_terms_last_changed' );
-add_action( 'updated_term_meta', 'wp_cache_set_terms_last_changed' );
-add_action( 'deleted_term_meta', 'wp_cache_set_terms_last_changed' );
+add_action( 'added_term_meta', 'wp_cache_set_terms_meta_last_changed' );
+add_action( 'updated_term_meta', 'wp_cache_set_terms_meta_last_changed' );
+add_action( 'deleted_term_meta', 'wp_cache_set_terms_meta_last_changed' );
 add_filter( 'get_term_metadata', 'wp_check_term_meta_support_prefilter' );
 add_filter( 'add_term_metadata', 'wp_check_term_meta_support_prefilter' );
 add_filter( 'update_term_metadata', 'wp_check_term_meta_support_prefilter' );
@@ -148,9 +148,9 @@
 add_filter( 'update_term_metadata_cache', 'wp_check_term_meta_support_prefilter' );
 
 // Comment meta.
-add_action( 'added_comment_meta', 'wp_cache_set_comments_last_changed' );
-add_action( 'updated_comment_meta', 'wp_cache_set_comments_last_changed' );
-add_action( 'deleted_comment_meta', 'wp_cache_set_comments_last_changed' );
+add_action( 'added_comment_meta', 'wp_cache_set_comments_meta_last_changed' );
+add_action( 'updated_comment_meta', 'wp_cache_set_comments_meta_last_changed' );
+add_action( 'deleted_comment_meta', 'wp_cache_set_comments_meta_last_changed' );
 add_action( 'init', 'wp_create_initial_comment_meta' );
 
 // Places to balance tags on input.

src/wp-includes/ms-default-filters.php

@@ -55,9 +55,9 @@
 add_action( 'update_blog_public', 'wp_update_blog_public_option_on_site_update', 1, 2 );
 
 // Site meta.
-add_action( 'added_blog_meta', 'wp_cache_set_sites_last_changed' );
-add_action( 'updated_blog_meta', 'wp_cache_set_sites_last_changed' );
-add_action( 'deleted_blog_meta', 'wp_cache_set_sites_last_changed' );
+add_action( 'added_blog_meta', 'wp_cache_set_sites_meta_last_changed' );
+add_action( 'updated_blog_meta', 'wp_cache_set_sites_meta_last_changed' );
+add_action( 'deleted_blog_meta', 'wp_cache_set_sites_meta_last_changed' );
 add_filter( 'get_blog_metadata', 'wp_check_site_meta_support_prefilter' );
 add_filter( 'add_blog_metadata', 'wp_check_site_meta_support_prefilter' );
 add_filter( 'update_blog_metadata', 'wp_check_site_meta_support_prefilter' );

src/wp-includes/ms-site.php

@@ -1320,6 +1320,18 @@ function wp_cache_set_sites_last_changed() {
 	wp_cache_set_last_changed( 'sites' );
 }
 
+/**
+ * Sets the last changed time for the 'sites-meta' cache group.
+ *
+ * This is used to invalidate site query caches that include meta queries,
+ * without affecting query caches for queries that do not use meta.
+ *
+ * @since x.x.x
+ */
+function wp_cache_set_sites_meta_last_changed() {
+	wp_cache_set_last_changed( 'sites-meta' );
+}
+
 /**
  * Aborts calls to site meta if it is not supported.
  *

src/wp-includes/post.php

@@ -8450,6 +8450,18 @@ function wp_cache_set_posts_last_changed() {
 	wp_cache_set_last_changed( 'posts' );
 }
 
+/**
+ * Sets the last changed time for the 'posts-meta' cache group.
+ *
+ * This is used to invalidate post query caches that include meta queries,
+ * without affecting query caches for queries that do not use meta.
+ *
+ * @since x.x.x
+ */
+function wp_cache_set_posts_meta_last_changed() {
+	wp_cache_set_last_changed( 'posts-meta' );
+}
+
 /**
  * Gets all available post MIME types for a given post type.
  *

src/wp-includes/taxonomy.php

@@ -5142,6 +5142,18 @@ function wp_cache_set_terms_last_changed() {
 	wp_cache_set_last_changed( 'terms' );
 }
 
+/**
+ * Sets the last changed time for the 'terms-meta' cache group.
+ *
+ * This is used to invalidate term query caches that include meta queries,
+ * without affecting query caches for queries that do not use meta.
+ *
+ * @since x.x.x
+ */
+function wp_cache_set_terms_meta_last_changed() {
+	wp_cache_set_last_changed( 'terms-meta' );
+}
+
 /**
  * Aborts calls to term meta if it is not supported.
  *

src/wp-includes/user.php

@@ -5239,6 +5239,18 @@ function wp_cache_set_users_last_changed() {
 	wp_cache_set_last_changed( 'users' );
 }
 
+/**
+ * Sets the last changed time for the 'users-meta' cache group.
+ *
+ * This is used to invalidate user query caches that include meta queries,
+ * without affecting query caches for queries that do not use meta.
+ *
+ * @since x.x.x
+ */
+function wp_cache_set_users_meta_last_changed() {
+	wp_cache_set_last_changed( 'users-meta' );
+}
+
 /**
  * Checks if password reset is allowed for a specific user.
  *