Ticket #46388: 46388.diff

src/wp-includes/class-wp-user.php

@@ -233 +233 @@
                 }
 
                 if ( false !== $user_id ) {
+                        // Prevent non-existent users from triggering multiple queries
+                        $notusers = wp_cache_get( 'notusers', 'users' );
+                        if ( isset( $notusers[ $user_id ] ) ) {
+                                return false;
+                        }
+
                         if ( $user = wp_cache_get( $user_id, 'users' ) ) {
                                 return $user;
                         }
@@ -244 +250 @@
                                 $value
                         )
                 ) ) {
+                        // User does not exist, so we must cache its non-existence
+                        if ( ! is_array( $notusers ) ) {
+                                $notusers = array();
+                        }
+
+                        $notusers[ $user_id ] = true;
+                        wp_cache_set( 'notusers', $notusers, 'users' );
+                        
                         return false;
                 }