mysql query optimization

I’ve whittled things down to the point where the only baseline change from WordPress 2.0.2 is in the next_posts_link function of the wp-includes/template-functions-links.php file. The change is necessary because WPopac rewrites the SQL search queries in a way that’s incompatible with a piece of this function, but necessary for performance reasons.

Here’s how my version reads:

`

function next_posts_link($label='Next Page »', $max_page=0) {
	global $paged, $result, $request, $posts_per_page, $wpdb, $max_num_pages;
	if ( !$max_page ) {
			if ( isset($max_num_pages) ) {
				$max_page = $max_num_pages;
			} else {
				preg_match('#FROM\s(.*)\sGROUP BY#siU', $request, $matches);

				// added April 5 2006 by Casey Bisson to support WPopac
				// necessary because the preg_match above fails with some queries
				if(!$fromwhere)
					$fromwhere = $wpdb->posts;
				
				// changed April 5 2006 by Casey Bisson to speed the query by eliminating
				// the slow DISTINCT clause
				//$numposts = $wpdb->get_var(“SELECT COUNT(DISTINCT ID) FROM $fromwhere”);
				$numposts = $wpdb->get_var(“SELECT COUNT(*) FROM $fromwhere”);
				$max_page = $max_num_pages = ceil($numposts / $posts_per_page);
			}
	}
	if ( !$paged )
		$paged = 1;
	$nextpage = intval($paged) + 1;
	if ( (! is_single()) && (empty($paged) || $nextpage < = $max_page) ) {
		echo '<a href=“';
		next_posts($max_page);
		echo '”>'. preg_replace('/&([^#])(?![a-z]{1,8};)/', '&$1', $label) .'</a>';
	}
}

`