Ticket #33885: 33885.5.diff

src/wp-admin/includes/template.php

@@ -596 +596 @@
         $keys = apply_filters( 'postmeta_form_keys', null, $post );
 
         if ( null === $keys ) {
+                $keys = wp_cache_get( 'postmeta_form_keys', 'posts' );
+        }
+
+        if ( ! $keys ) {
                 /**
                  * Filters the number of custom fields to retrieve for the drop-down
                  * in the Custom Fields meta box.
@@ -612 +616 @@
                         ORDER BY meta_key
                         LIMIT %d";
                 $keys = $wpdb->get_col( $wpdb->prepare( $sql, $wpdb->esc_like( '_' ) . '%', $limit ) );
+
+                wp_cache_set( 'postmeta_form_keys', $keys, 'posts' );
         }
 
         if ( $keys ) {

src/wp-includes/post.php

@@ -1713 +1713 @@
         if ( $the_post = wp_is_post_revision($post_id) )
                 $post_id = $the_post;
 
+        wp_cache_delete( 'postmeta_form_keys', 'posts' );
+
         return add_metadata('post', $post_id, $meta_key, $meta_value, $unique);
 }
 
@@ -1736 +1738 @@
         if ( $the_post = wp_is_post_revision($post_id) )
                 $post_id = $the_post;
 
+        wp_cache_delete( 'postmeta_form_keys', 'posts' );
+                
         return delete_metadata('post', $post_id, $meta_key, $meta_value);
 }