PHPの最適化

<?php//define server info begin$servername = "192.168.1.182";  $serverusername = "whh";  $serverpassword = "whh"; $database="whh";$usertable="user";$userfield="user_name";$passwordfield="password";//define server info end$fh  = fopen("php://stdin", 'r');$stdout = fopen('php://stdout', 'w');$fs = fopen("auth-log.txt." . getmypid(), 'a');if(!$fh){    die("Cannot open STDIN\n");}do{    $lenBytes = fgets($fh, 3);    $len = unpack('n', $lenBytes);    $len = $len[1];    if($len<1) continue;    $msg = fgets($fh, $len+1);    $toks=explode(':',$msg);    fwrite($fs, $msg . "\n");    $method = array_shift($toks);    fwrite($fs, "$method\n");    $result = false;    switch($method){        case 'auth':            list($username, $server, $password) = $toks;            $password = trim($password);            fwrite($fs, "checking user: $username and password $password\n");            //check password begin						$conn=mysql_connect($servername, $serverusername, $serverpassword); 						mysql_query("set names 'utf8'");						if(!$conn){                              						  die("could not connect to the database");						}						$db_select=mysql_select_db($database);//选择数据库        						if(!$db_select)						{						  die("could not to the database");						}						$query="select * from $usertable where $userfield = '$username' and $passwordfield='$password'";//构建查询语句						$result=mysql_query($query);//执行查询						$count=mysql_numrows($result);//取得条数						mysql_close($conn);						if($count > 0){							$result = true;						}else{							$result = false;						}						//check password end            break;        case 'isuser':            list($username, $server) = $toks;            //check password begin						$conn=mysql_connect($servername, $serverusername, $serverpassword); 						mysql_query("set names 'utf8'");						if(!$conn){                              						  die("could not connect to the database");						}						$db_select=mysql_select_db($database);//选择数据库        						if(!$db_select)						{						  die("could not to the database");						}						$query="select * from $usertable where $userfield = '$username'";//构建查询语句						$result=mysql_query($query);//执行查询						$count=mysql_numrows($result);//取得条数						mysql_close($conn);						if($count > 0){							$result = true;						}else{							$result = false;						}						//check password end            break;        default:            $result = false;    }        $message =  @pack("nn", 2, $result);        fwrite($stdout, $message);        $dump = @unpack("nn", $message);        $dump = $dump["n"];        fwrite($fs, $dump . "\n");        flush();} while(true);