From cfafcf3997b5d09e57fc8f66da26dde8d666894a Mon Sep 17 00:00:00 2001 From: Gary Pendergast Date: Tue, 9 Aug 2016 11:38:41 +0000 Subject: [PATCH] Multisite: Improve performance of the upgrade page on large networks. The query to select the next 5 blogs to upgrade was ordered by `registered`, which isn't indexed. This causes the query to table scan, which will be slow on networks with many blogs. The query only needs to be ordered by something that won't change, so ordering by `blog_id` is a good replacement. `blog_id` is indexed, and it's the only column being returned, so MySQL is able to optimize for a fast index read. Props fliespl. Fixes #37612. git-svn-id: https://develop.svn.wordpress.org/trunk@38229 602fd350-edb4-49c9-b593-d223f7449a82 --- src/wp-admin/network/upgrade.php | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/wp-admin/network/upgrade.php b/src/wp-admin/network/upgrade.php index 199838cf57..ee8fd57545 100644 --- a/src/wp-admin/network/upgrade.php +++ b/src/wp-admin/network/upgrade.php @@ -55,7 +55,7 @@ switch ( $action ) { update_site_option( 'wpmu_upgrade_site', $wp_db_version ); } - $blogs = $wpdb->get_results( "SELECT blog_id FROM {$wpdb->blogs} WHERE site_id = '{$wpdb->siteid}' AND spam = '0' AND deleted = '0' AND archived = '0' ORDER BY registered DESC LIMIT {$n}, 5", ARRAY_A ); + $blogs = $wpdb->get_results( "SELECT blog_id FROM {$wpdb->blogs} WHERE site_id = '{$wpdb->siteid}' AND spam = '0' AND deleted = '0' AND archived = '0' ORDER BY blog_id DESC LIMIT {$n}, 5", ARRAY_A ); if ( empty( $blogs ) ) { echo '

' . __( 'All done!' ) . '

'; break;