PHP persistent connection mysql_pconnect usage example

$conn = mysql_pconnect($host,$user,$pwd);
mysql_select_db($dbname,$conn);
$result=mysql_query("select * from table_name where col_id =' test_id'", $conn);
$result_detail=mysql_fetch_array($result);
$item = $result_detail['col_id'];
?>

Note: as a high-concurrency processing database When requesting, using mysql_pconnect is not a good choice. At this time, issues such as caching and decentralization can be considered.