Changeset 34270

Timestamp:

09/17/2015 08:00:31 PM (9 years ago)

Author:

boonebgorges

Message:

Lazy-load comment meta on single post pages.

[34268] introduced cache priming for commentmeta, enabled by default. To
ensure performance on single post pages - where commentmeta is most likely
to cause performance issues - we disable up-front cache-priming. Instead, we
prime commentmeta caches for all comments in the loop the first time
get_comment_meta() is called on the page.

Props bradt, dd32, wonderboymusic, boonebgorges.
Fixes #16894.

Location:

trunk

Files:

• src/wp-includes/comment-functions.php (modified) (1 diff)
• src/wp-includes/comment-template.php (modified) (1 diff)
• src/wp-includes/default-filters.php (modified) (1 diff)
• tests/phpunit/tests/comment/metaCache.php (modified) (2 diffs)

trunk/src/wp-includes/comment-functions.php

@@ -2377 +2377 @@
 }
 
+/**
+ * Lazy load comment meta when inside of a `WP_Query` loop.
+ *
+ * @since 4.4.0
+ *
+ * @param null $check      The `$check` param passed from the 'pre_comment_metadata' hook.
+ * @param int  $comment_id ID of the comment whose metadata is being cached.
+ * @return null In order not to short-circuit `get_metadata()`.
+ */
+function wp_lazyload_comment_meta( $check, $comment_id ) {
+    global $wp_query;
+
+    if ( ! empty( $wp_query->comments ) ) {
+        // Don't use `wp_list_pluck()` to avoid by-reference manipulation.
+        $comment_ids = array();
+        foreach ( $wp_query->comments as $comment ) {
+            $comment_ids[] = $comment->comment_ID;
+        }
+        update_meta_cache( 'comment', $comment_ids );
+    }
+
+    return $check;
+}
+
 //
 // Internal

trunk/src/wp-includes/comment-template.php

@@ -1212 +1212 @@
         'status'  => 'approve',
         'post_id' => $post->ID,
+        'update_comment_meta_cache' => false, // We lazy-load comment meta for performance.
     );
 

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

@@ -201 +201 @@
 add_filter( 'xmlrpc_pingback_error',    'xmlrpc_pingback_error'               );
 add_filter( 'title_save_pre',           'trim'                                );
+add_filter( 'get_comment_metadata',     'wp_lazyload_comment_meta',     10, 2 );
 
 add_filter( 'http_request_host_is_external', 'allowed_http_request_hosts', 10, 2 );

trunk/tests/phpunit/tests/comment/metaCache.php

@@ -82 +82 @@
     }
 
-    public function test_comment_meta_cache() {
-        $post_id = $this->factory->post->create( array(
-            'post_status' => 'publish'
-        ) );
+    /**
+     * @ticket 16894
+     */
+    public function test_comment_meta_should_be_lazy_loaded_for_all_comments_in_comments_template() {
+        global $wpdb;
 
-        $comment_ids = $this->factory->comment->create_post_comments( $post_id, 10 );
+        $p = $this->factory->post->create( array( 'post_status' => 'publish' ) );
+        $comment_ids = $this->factory->comment->create_post_comments( $p, 3 );
 
         foreach ( $comment_ids as $cid ) {
@@ -93 +95 @@
         }
 
-        $post = get_post( $post_id );
+        $this->go_to( get_permalink( $p ) );
 
-        $this->assertEquals( $post->comment_count, count( $comment_ids ) );
+        if ( have_posts() ) {
+            while ( have_posts() ) {
+                the_post();
 
-        $this->go_to( get_permalink( $post_id ) );
+                // Load comments with `comments_template()`.
+                $cform = get_echo( 'comments_template' );
 
-        $this->assertTrue( is_single() );
-        $this->assertTrue( have_posts() );
+                // First request will hit the database.
+                $num_queries = $wpdb->num_queries;
+                get_comment_meta( $comment_ids[0], 'sauce' );
+                $this->assertSame( $num_queries + 1, $wpdb->num_queries );
 
-        global $wp_query;
-
-        while ( have_posts() ) {
-            the_post();
-
-            $comment_args = array(
-                'order'   => 'ASC',
-                'orderby' => 'comment_date_gmt',
-                'status'  => 'approve',
-                'post_id' => get_the_ID(),
-            );
-
-            $comments = get_comments( $comment_args );
-
-            // This is beyond awful
-            $wp_query->comments = $comments;
-
-            wp_list_comments( array(
-                'echo' => false,
-                'callback' => array( $this, '_comment_callback' )
-            ) );
+                // Second and third requests should be in cache.
+                get_comment_meta( $comment_ids[1], 'sauce' );
+                get_comment_meta( $comment_ids[2], 'sauce' );
+                $this->assertSame( $num_queries + 1, $wpdb->num_queries );
+            }
         }
     }
-
-    public function _comment_callback( $comment ) {
-        global $wpdb;
-
-        get_comment_meta( $comment->comment_ID, 'sauce' );
-
-        if ( 0 === $this->i ) {
-            $this->queries = $wpdb->num_queries;
-        } else {
-            $this->assertEquals( $this->queries, $wpdb->num_queries );
-        }
-
-        $this->i++;
-    }
 }