Changeset 34711

Timestamp:

09/30/2015 01:34:54 AM (9 years ago)

Author:

boonebgorges

Message:

Improve lazyloading of comment meta in WP_Query loops.

Lazy-loading logic is moved to a method on WP_Query. This makes it possible
for comment feeds to take advantage of metadata lazyloading, in addition to
comments loaded via comments_template().

This new technique parallels the termmeta lazyloading technique introduced in
[34704].

Fixes #34047.

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)
• src/wp-includes/query.php (modified) (3 diffs)
• tests/phpunit/tests/comment/metaCache.php (modified) (1 diff)

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

@@ -2453 +2453 @@
 }
 
-/**
- * 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

@@ -1321 +1321 @@
      */
     $wp_query->comments = apply_filters( 'comments_array', $comments_flat, $post->ID );
+
+    // Set up lazy-loading for comment metadata.
+    add_action( 'get_comment_metadata', array( $wp_query, 'lazyload_comment_meta' ), 10, 2 );
+
     $comments = &$wp_query->comments;
     $wp_query->comment_count = count($wp_query->comments);

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/src/wp-includes/query.php

@@ -1311 +1311 @@
      */
     public $updated_term_meta_cache = false;
+
+    /**
+     * Whether the comment meta cache for matched posts has been primed.
+     *
+     * @since 4.4.0
+     * @access protected
+     * @var bool
+     */
+    public $updated_comment_meta_cache = false;
 
     /**
@@ -3683 +3692 @@
         }
 
+        // If comments have been fetched as part of the query, make sure comment meta lazy-loading is set up.
+        if ( ! empty( $this->comments ) ) {
+            add_action( 'get_comment_metadata', array( $this, 'lazyload_comment_meta' ), 10, 2 );
+        }
+
         if ( ! $q['suppress_filters'] ) {
             /**
@@ -4817 +4831 @@
         return $check;
     }
+
+    /**
+     * Lazy-load comment meta when inside of a `WP_Query` loop.
+     *
+     * This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it
+     * directly, from either inside or outside the `WP_Query` object.
+     *
+     * @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()`.
+     */
+    public function lazyload_comment_meta( $check, $comment_id ) {
+        /*
+         * We only do this once per `WP_Query` instance.
+         * Can't use `remove_action()` because of non-unique object hashes.
+         */
+        if ( $this->updated_comment_meta_cache ) {
+            return $check;
+        }
+
+        // Don't use `wp_list_pluck()` to avoid by-reference manipulation.
+        $comment_ids = array();
+        if ( is_array( $this->comments ) ) {
+            foreach ( $this->comments as $comment ) {
+                $comment_ids[] = $comment->comment_ID;
+            }
+        }
+
+        /*
+         * Only update the metadata cache for comments belonging to these posts if the comment_id passed
+         * to `get_comment_meta()` matches one of those comments. This prevents a single call to
+         * `get_comment_meta()` from priming metadata for all `WP_Query` objects.
+         */
+        if ( in_array( $comment_id, $comment_ids ) ) {
+            update_meta_cache( 'comment', $comment_ids );
+            $this->updated_comment_meta_cache = true;
+        } elseif ( empty( $comment_ids ) ) {
+            $this->updated_comment_meta_cache = true;
+        }
+
+        return $check;
+    }
 }
 

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

@@ -122 +122 @@
         }
     }
+
+    /**
+     * @group 34047
+     */
+    public function test_comment_meta_should_be_lazy_loaded_in_comment_feed_queries() {
+        global $wpdb;
+
+        $posts = $this->factory->post->create_many( 2, array( 'post_status' => 'publish' ) );
+
+        $now = time();
+        $comments = array();
+        for ( $i = 0; $i < 5; $i++ ) {
+            $comments[] = $this->factory->comment->create( array(
+                'comment_post_ID' => $posts[0],
+                'comment_date_gmt' => date( 'Y-m-d H:i:s', $now - ( 60 * $i ) ),
+            ) );
+        }
+
+        foreach ( $comments as $c ) {
+            add_comment_meta( $c, 'foo', 'bar' );
+        }
+
+        update_option( 'posts_per_rss', 3 );
+
+        $q = new WP_Query( array(
+            'feed' => true,
+            'withcomments' => true,
+        ) );
+
+        // First comment will cause the cache to be primed.
+        $num_queries = $wpdb->num_queries;
+        $this->assertSame( 'bar', get_comment_meta( $comments[0], 'foo', 'bar' ) );
+        $num_queries++;
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+
+        // Second comment from the results should not cause more queries.
+        $this->assertSame( 'bar', get_comment_meta( $comments[1], 'foo', 'bar' ) );
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+
+        // A comment from outside the results will not be primed.
+        $this->assertSame( 'bar', get_comment_meta( $comments[4], 'foo', 'bar' ) );
+        $num_queries++;
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+    }
+
+    /**
+     * @group 34047
+     */
+    public function test_comment_meta_should_be_lazy_loaded_in_single_post_comment_feed_queries() {
+        global $wpdb;
+
+        $posts = $this->factory->post->create_many( 2, array( 'post_status' => 'publish' ) );
+
+        $now = time();
+        $comments = array();
+        for ( $i = 0; $i < 5; $i++ ) {
+            $comments[] = $this->factory->comment->create( array(
+                'comment_post_ID' => $posts[0],
+                'comment_date_gmt' => date( 'Y-m-d H:i:s', $now - ( 60 * $i ) ),
+            ) );
+        }
+
+        foreach ( $comments as $c ) {
+            add_comment_meta( $c, 'foo', 'bar' );
+        }
+
+        update_option( 'posts_per_rss', 3 );
+
+        $q = new WP_Query( array(
+            'feed' => true,
+            'withcomments' => true,
+            'p' => $posts[0],
+        ) );
+
+        // First comment will cause the cache to be primed.
+        $num_queries = $wpdb->num_queries;
+        $this->assertSame( 'bar', get_comment_meta( $comments[0], 'foo', 'bar' ) );
+        $num_queries++;
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+
+        // Second comment from the results should not cause more queries.
+        $this->assertSame( 'bar', get_comment_meta( $comments[1], 'foo', 'bar' ) );
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+
+        // A comment from outside the results will not be primed.
+        $this->assertSame( 'bar', get_comment_meta( $comments[4], 'foo', 'bar' ) );
+        $num_queries++;
+        $this->assertSame( $num_queries, $wpdb->num_queries );
+    }
 }