Changeset 56763

Timestamp:

10/03/2023 02:59:22 PM (12 months ago)

Author:

spacedmonkey

Message:

Query: Improve caching behavior for WP_Query when retrieving id=>parent fields

In [53941], the addition of query caching to WP_Query brought about an unintended issue when querying for fields equal to id=>parent. Specifically, on websites with object caching enabled and a substantial number of pages, the second run of this query triggered the _prime_post_caches function for id=>parent. This led to the unnecessary priming of post, meta, and term caches, even when only id and parent information were requested.

This commit addresses this issue by introducing a new function, _prime_post_parents_caches, which primes a dedicated cache for post parents. This cache is primed during the initial query execution. Subsequently, the wp_cache_get_multiple function is employed to retrieve all post parent data in a single object cache request, optimizing performance.

Additionally, this commit extends the coverage of existing unit tests to ensure the reliability of the changes.

Props kevinfodness, joemcgill, peterwilsoncc, LinSoftware, thekt12, spacedmonkey.
Fixes #59188

Location:

trunk

Files:

• src/wp-includes/class-wp-query.php (modified) (2 diffs)
• src/wp-includes/functions.php (modified) (1 diff)
• src/wp-includes/post.php (modified) (2 diffs)
• tests/phpunit/tests/post/primePostParentsCaches.php (added)
• tests/phpunit/tests/query/cacheResults.php (modified) (2 diffs)

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

@@ -3180 +3180 @@
 
                 if ( $cached_results ) {
-                    if ( 'ids' === $q['fields'] ) {
-                        /** @var int[] */
-                        $this->posts = array_map( 'intval', $cached_results['posts'] );
-                    } else {
-                        _prime_post_caches( $cached_results['posts'], $q['update_post_term_cache'], $q['update_post_meta_cache'] );
-                        /** @var WP_Post[] */
-                        $this->posts = array_map( 'get_post', $cached_results['posts'] );
-                    }
-
-                    $this->post_count    = count( $this->posts );
+                    /** @var int[] */
+                    $post_ids = array_map( 'intval', $cached_results['posts'] );
+
+                    $this->post_count    = count( $post_ids );
                     $this->found_posts   = $cached_results['found_posts'];
                     $this->max_num_pages = $cached_results['max_num_pages'];
 
                     if ( 'ids' === $q['fields'] ) {
+                        $this->posts = $post_ids;
+
                         return $this->posts;
                     } elseif ( 'id=>parent' === $q['fields'] ) {
+                        _prime_post_parents_caches( $post_ids );
+
                         /** @var int[] */
-                        $post_parents = array();
-
-                        foreach ( $this->posts as $key => $post ) {
+                        $post_parents = wp_cache_get_multiple( $post_ids, 'post_parent' );
+
+                        foreach ( $post_parents as $id => $post_parent ) {
                             $obj              = new stdClass();
-                            $obj->ID          = (int) $post->ID;
-                            $obj->post_parent = (int) $post->post_parent;
-
-                            $this->posts[ $key ] = $obj;
-
-                            $post_parents[ $obj->ID ] = $obj->post_parent;
+                            $obj->ID          = (int) $id;
+                            $obj->post_parent = (int) $post_parent;
+
+                            $this->posts[] = $obj;
                         }
 
                         return $post_parents;
+                    } else {
+                        _prime_post_caches( $post_ids, $q['update_post_term_cache'], $q['update_post_meta_cache'] );
+                        /** @var WP_Post[] */
+                        $this->posts = array_map( 'get_post', $post_ids );
                     }
                 }
@@ -3257 +3257 @@
                 $post_ids[]                      = (int) $post->ID;
             }
+            // Prime post parent caches, so that on second run, there is not another database query.
+            wp_cache_add_multiple( $post_parents, 'post_parent' );
 
             if ( $q['cache_results'] && $id_query_is_cacheable ) {

trunk/src/wp-includes/functions.php

@@ -7170 +7170 @@
 
     foreach ( $cache_values as $id => $value ) {
-        if ( ! $value ) {
+        if ( false === $value ) {
             $non_cached_ids[] = (int) $id;
         }

trunk/src/wp-includes/post.php

@@ -7263 +7263 @@
     wp_cache_delete( $post->ID, 'posts' );
     wp_cache_delete( $post->ID, 'post_meta' );
+    wp_cache_delete( $post->ID, 'post_parent' );
 
     clean_object_term_cache( $post->ID, $post->post_type );
@@ -7797 +7798 @@
 
 /**
+ * Prime post parent caches.
+ *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param int[] $ids ID list.
+ */
+function _prime_post_parents_caches( array $ids ) {
+    global $wpdb;
+
+    $non_cached_ids = _get_non_cached_ids( $ids, 'post_parent' );
+    if ( ! empty( $non_cached_ids ) ) {
+        $fresh_posts = $wpdb->get_results( sprintf( "SELECT $wpdb->posts.ID, $wpdb->posts.post_parent FROM $wpdb->posts WHERE ID IN (%s)", implode( ',', $non_cached_ids ) ) );
+
+        if ( $fresh_posts ) {
+            $post_parent_data = array();
+            foreach ( $fresh_posts as $fresh_post ) {
+                $post_parent_data[ (int) $fresh_post->ID ] = (int) $fresh_post->post_parent;
+            }
+
+            wp_cache_add_multiple( $post_parent_data, 'post_parent' );
+        }
+    }
+}
+
+/**
  * Adds a suffix if any trashed posts have a given slug.
  *

trunk/tests/phpunit/tests/query/cacheResults.php

@@ -711 +711 @@
         $queries_after = get_num_queries();
 
-        $this->assertSame( $queries_before, $queries_after );
+        $this->assertSame( 1, $queries_after - $queries_before );
         $this->assertCount( 5, $query1->posts );
         $this->assertCount( 5, $query2->posts );
@@ -725 +725 @@
          */
         $this->assertNotEquals( $query1->posts, $query2->posts );
+    }
+
+
+    /**
+     * @ticket 59188
+     */
+    public function test_query_cache_unprimed_parents() {
+        $args   = array(
+            'cache_results' => true,
+            'fields'        => 'id=>parent',
+        );
+        $query1 = new WP_Query();
+        $query1->query( $args );
+
+        $post_ids = wp_list_pluck( $query1->posts, 'ID' );
+        wp_cache_delete_multiple( $post_ids, 'post_parent' );
+
+        $queries_before = get_num_queries();
+        $query2         = new WP_Query();
+        $query2->query( $args );
+        $queries_after = get_num_queries();
+
+        $this->assertSame( 1, $queries_after - $queries_before, 'There should be only one query to prime parents' );
+        $this->assertCount( 5, $query1->posts, 'There should be only 5 posts returned on first query' );
+        $this->assertCount( 5, $query2->posts, 'There should be only 5 posts returned on second query' );
+        $this->assertSame( $query1->found_posts, $query2->found_posts, 'Found posts should match on second query' );
+    }
+
+    /**
+     * @ticket 59188
+     */
+    public function test_query_cache_update_parent() {
+        $page_id = self::factory()->post->create(
+            array(
+                'post_type'   => 'page',
+                'post_parent' => self::$pages[0],
+            )
+        );
+        $args    = array(
+            'cache_results' => true,
+            'post_type'     => 'page',
+            'fields'        => 'id=>parent',
+            'post__in'      => array(
+                $page_id,
+            ),
+        );
+        $query1  = new WP_Query();
+        $query1->query( $args );
+
+        wp_update_post(
+            array(
+                'ID'          => $page_id,
+                'post_parent' => self::$pages[1],
+            )
+        );
+
+        $queries_before = get_num_queries();
+        $query2         = new WP_Query();
+        $query2->query( $args );
+        $queries_after = get_num_queries();
+
+        $this->assertSame( self::$pages[0], $query1->posts[0]->post_parent, 'Check post parent on first query' );
+        $this->assertSame( self::$pages[1], $query2->posts[0]->post_parent, 'Check post parent on second query' );
+        $this->assertSame( 2, $queries_after - $queries_before, 'There should be 2 queries, one for id=>parent' );
+        $this->assertSame( $query1->found_posts, $query2->found_posts, 'Found posts should match on second query' );
+    }
+
+    /**
+     * @ticket 59188
+     */
+    public function test_query_cache_delete_parent() {
+        $parent_page_id = self::factory()->post->create(
+            array(
+                'post_type' => 'page',
+            )
+        );
+        $page_id        = self::factory()->post->create(
+            array(
+                'post_type'   => 'page',
+                'post_parent' => $parent_page_id,
+            )
+        );
+        $args           = array(
+            'cache_results' => true,
+            'post_type'     => 'page',
+            'fields'        => 'id=>parent',
+            'post__in'      => array(
+                $page_id,
+            ),
+        );
+        $query1         = new WP_Query();
+        $query1->query( $args );
+
+        wp_delete_post( $parent_page_id, true );
+
+        $queries_before = get_num_queries();
+        $query2         = new WP_Query();
+        $query2->query( $args );
+        $queries_after = get_num_queries();
+
+        $this->assertSame( $parent_page_id, $query1->posts[0]->post_parent, 'Check post parent on first query' );
+        $this->assertSame( 0, $query2->posts[0]->post_parent, 'Check post parent on second query' );
+        $this->assertSame( 2, $queries_after - $queries_before, 'There should be 2 queries, one for id=>parent' );
+        $this->assertSame( $query1->found_posts, $query2->found_posts, 'Found posts should match on second query' );
     }