$re = '/(.+?)[ ]?((?<=[ ])\(cost=([\d\.]+)[ ]rows=(\d+)\))?[ ]\(actual[ ]time=([\d\.]+)[ ]rows=(\d+)[ ]loops=(\d+)\)/m';
$str = 'Single-row index lookup on using <auto_distinct_key> (actor_id=actor.actor_id) (cost=901.66 rows=5478) (actual time=0.001..0.001 rows=0 loops=200)
Single-row index lookup on using <auto_distinct_key> (actor_id=actor.actor_id) (actual time=0.001..0.001 rows=0 loops=200)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php