Multisite: Improve performance by caching not found lookups for sites and networks.

With this change, the result of a site or network lookup by ID will be cached even if the ID does not exist. When a new site or network is created, the cache for the respective new ID is cleared.

Props mnelson4, nielsdeblaauw.
Fixes #42251.

Built from https://develop.svn.wordpress.org/trunk@45910


git-svn-id: http://core.svn.wordpress.org/trunk@45721 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/schema.php

@@ -1159,6 +1159,12 @@ function populate_network_meta( $network_id, array $meta = array() ) {
 		}
 	}
 
+	if ( function_exists( 'clean_network_cache' ) ) {
+		clean_network_cache( $network_id );
+	} else {
+		wp_cache_delete( $network_id, 'networks' );
+	}
+
 	wp_cache_delete( 'networks_have_paths', 'site-options' );
 
 	if ( ! is_multisite() ) {

wp-includes/class-wp-network.php

@@ -101,16 +101,20 @@ class WP_Network {
 
 		$_network = wp_cache_get( $network_id, 'networks' );
 
-		if ( ! $_network ) {
+		if ( false === $_network ) {
 			$_network = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->site} WHERE id = %d LIMIT 1", $network_id ) );
 
 			if ( empty( $_network ) || is_wp_error( $_network ) ) {
-				return false;
+				$_network = -1;
 			}
 
 			wp_cache_add( $network_id, $_network, 'networks' );
 		}
 
+		if ( is_numeric( $_network ) ) {
+			return false;
+		}
+
 		return new WP_Network( $_network );
 	}
 
@@ -231,8 +235,8 @@ class WP_Network {
 			return (int) $this->blog_id;
 		}
 
-		if ( ( defined( 'DOMAIN_CURRENT_SITE' ) && defined( 'PATH_CURRENT_SITE' ) && $this->domain === DOMAIN_CURRENT_SITE && $this->path === PATH_CURRENT_SITE )
-			|| ( defined( 'SITE_ID_CURRENT_SITE' ) && $this->id == SITE_ID_CURRENT_SITE ) ) {
+		if ( ( defined( 'DOMAIN_CURRENT_SITE' ) && defined( 'PATH_CURRENT_SITE' ) && DOMAIN_CURRENT_SITE === $this->domain && PATH_CURRENT_SITE === $this->path )
+			|| ( defined( 'SITE_ID_CURRENT_SITE' ) && SITE_ID_CURRENT_SITE == $this->id ) ) {
 			if ( defined( 'BLOG_ID_CURRENT_SITE' ) ) {
 				$this->blog_id = (string) BLOG_ID_CURRENT_SITE;
 
@@ -457,7 +461,7 @@ class WP_Network {
 					break;
 				}
 			}
-			if ( $network->path === '/' ) {
+			if ( '/' === $network->path ) {
 				$found = true;
 				break;
 			}

wp-includes/class-wp-site.php

@@ -162,16 +162,20 @@ final class WP_Site {
 
 		$_site = wp_cache_get( $site_id, 'sites' );
 
-		if ( ! $_site ) {
+		if ( false === $_site ) {
 			$_site = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->blogs} WHERE blog_id = %d LIMIT 1", $site_id ) );
 
 			if ( empty( $_site ) || is_wp_error( $_site ) ) {
-				return false;
+				$_site = -1;
 			}
 
 			wp_cache_add( $site_id, $_site, 'sites' );
 		}
 
+		if ( is_numeric( $_site ) ) {
+			return false;
+		}
+
 		return new WP_Site( $_site );
 	}
 

wp-includes/ms-site.php

@@ -69,14 +69,14 @@ function wp_insert_site( array $data ) {
 		return new WP_Error( 'db_insert_error', __( 'Could not insert site into the database.' ), $wpdb->last_error );
 	}
 
+	clean_blog_cache( $wpdb->insert_id );
+
 	$new_site = get_site( $wpdb->insert_id );
 
 	if ( ! $new_site ) {
 		return new WP_Error( 'get_site_error', __( 'Could not retrieve site data.' ) );
 	}
 
-	clean_blog_cache( $new_site );
-
 	/**
 	 * Fires once a site has been inserted into the database.
 	 *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45909';
+$wp_version = '5.3-alpha-45910';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.