post numbers 1 for latest

function setPostNumbers() {
/* numbering the published posts: preparation: create an array with the ID in sequence of publication date, /
/ save the number in custom field '_post_number' of post with ID /
/ to show in post (within the loop) use <?php echo get_post_meta($post->ID,'_post_number',true); ?>
/ alchymyth 2010 */
global $wpdb;
$querystr = "SELECT $wpdb->posts.* FROM $wpdb->posts WHERE $wpdb->posts.post_status = 'publish' AND $wpdb->posts.post_type = 'post'  ";
$pageposts = $wpdb->get_results($querystr, OBJECT);
$counts = count($pageposts)+1 ;
if ($pageposts):
foreach ($pageposts as $post):
setup_postdata($post);
$counts--;
add_post_meta($post->ID, '_post_number', $counts, true);
update_post_meta($post->ID, '_post_number', $counts);
endforeach;
endif;
}
add_action ( 'publish_post', 'setPostNumbers' );
add_action ( 'deleted_post', 'setPostNumbers' );
add_action ( 'edit_post', 'setPostNumbers' );