3 normal queries query("SELECT id from users where age > 21"); while($row = mysqli_fetch_assoc($result)) { $ids[] = $row['id']; } } ]]> 3 async queries query("SELECT id from users where age > 21", MYSQLI_ASYNC); } $all_dbs = $read = $err = $rej = $dbs; do { if (!mysqli_poll($read, $err, $rej, 1)) { continue; } foreach($all_dbs as $id => $db) { if ($result = mysqli_reap_async_query($db)) { while($row = mysqli_fetch_assoc($result)) { $ids[] = $row['id']; } mysqli_free_result($result); unset($all_dbs[$id]); } } } while (count($all_dbs) > 0); ]]>