+
+ /*
+ * Deletes all expired transients. The multi-table delete syntax is used
+ * to delete the transient record from table a, and the corresponding
+ * transient_timeout record from table b.
+ */
+ $time = time();
+ $sql = "DELETE a, b FROM $wpdb->options a, $wpdb->options b
+ WHERE a.option_name LIKE %s
+ AND a.option_name NOT LIKE %s
+ AND b.option_name = CONCAT( '_transient_timeout_', SUBSTRING( a.option_name, 12 ) )
+ AND b.option_value < %d";
+ $wpdb->query( $wpdb->prepare( $sql, $wpdb->esc_like( '_transient_' ) . '%', $wpdb->esc_like( '_transient_timeout_' ) . '%', $time ) );
+
+ if ( is_main_site() && is_main_network() ) {
+ $sql = "DELETE a, b FROM $wpdb->options a, $wpdb->options b
+ WHERE a.option_name LIKE %s
+ AND a.option_name NOT LIKE %s
+ AND b.option_name = CONCAT( '_site_transient_timeout_', SUBSTRING( a.option_name, 17 ) )
+ AND b.option_value < %d";
+ $wpdb->query( $wpdb->prepare( $sql, $wpdb->esc_like( '_site_transient_' ) . '%', $wpdb->esc_like( '_site_transient_timeout_' ) . '%', $time ) );
+ }