From b7198b85f8b2cdd39129f05c1fde299472cabd94 Mon Sep 17 00:00:00 2001
From: Andrew Nacin <nacin@git.wordpress.org>
Date: Sat, 22 Sep 2012 15:55:02 +0000
Subject: [PATCH] Stop cleaning the cache of a post's children. Ancestors are
 no longer cached against the post object, which means this kind of walking is
 unnecessary. It is also prohibitively expensive with large hierarchies.

We need to remove post_ancestors non-persistent caching for this. get_post_ancestors() can simply rely on the caching of get_post() instead. Previously, it was a direct query, hence the extra layers of caching and clearing.

Child cache clearing stays in wp_delete_post() as children get a new parent.

fixes #11399.



git-svn-id: https://develop.svn.wordpress.org/trunk@21952 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-includes/load.php |  2 +-
 wp-includes/post.php | 17 ++---------------
 2 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/wp-includes/load.php b/wp-includes/load.php
index 7ad0341fb0..f998596525 100644
--- a/wp-includes/load.php
+++ b/wp-includes/load.php
@@ -410,7 +410,7 @@ function wp_start_object_cache() {
 
 	if ( function_exists( 'wp_cache_add_global_groups' ) ) {
 		wp_cache_add_global_groups( array( 'users', 'userlogins', 'usermeta', 'user_meta', 'site-transient', 'site-options', 'site-lookup', 'blog-lookup', 'blog-details', 'rss', 'global-posts' ) );
-		wp_cache_add_non_persistent_groups( array( 'comment', 'counts', 'plugins', 'post_ancestors' ) );
+		wp_cache_add_non_persistent_groups( array( 'comment', 'counts', 'plugins' ) );
 	}
 }
 
diff --git a/wp-includes/post.php b/wp-includes/post.php
index cac125efc7..613c2f4f6c 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -557,7 +557,6 @@ function get_post_ancestors( $post ) {
 
 	$post = get_post( $post );
 
-	if ( ! $ancestors = wp_cache_get( $post->ID, 'post_ancestors' ) ) {
 		$ancestors = array();
 
 		if ( !empty( $post->post_parent ) && $post->ID != $post->post_parent ) {
@@ -572,9 +571,6 @@ function get_post_ancestors( $post ) {
 			}
 		}
 
-		wp_cache_add( $post->ID, $ancestors, 'post_ancestors' );
-	}
-
 	return $ancestors;
 }
 
@@ -2218,8 +2214,8 @@ function wp_delete_post( $postid = 0, $force_delete = false ) {
 
 	clean_post_cache( $post );
 
-	if ( is_post_type_hierarchical( $post->post_type ) ) {
-		foreach ( (array) $children as $child )
+	if ( is_post_type_hierarchical( $post->post_type ) && $children ) {
+		foreach ( $children as $child )
 			clean_post_cache( $child );
 	}
 
@@ -4500,15 +4496,6 @@ function clean_post_cache( $post ) {
 		wp_cache_delete( 'all_page_ids', 'posts' );
 		do_action( 'clean_page_cache', $post->ID );
 	}
-
-	if ( $children = $wpdb->get_results( $wpdb->prepare("SELECT ID, post_type FROM $wpdb->posts WHERE post_parent = %d", $post->ID) ) ) {
-		foreach ( $children as $child ) {
-			// Loop detection
-			if ( $child->ID == $post->ID )
-				continue;
-			clean_post_cache( $child );
-		}
-	}
 }
 
 /**