在PHP脚本的末尾关闭和/或杀死mysqli连接?

Do I need to explicitly kill and/or close a mysqli connection at the end of a script. At the moment, I do neither, and it works, but I don't have much load.

I've heard that there is connection pooling, and mysqli connections are re-used... do I need to close the connection then at all?

No it is not necessary to close a mysql connection at the end of a script. PHP does it automatically.

You should always close your connections at the end of the main script. If you uses some php5 and object to handle your DB just think about using __destruct() to automatically close it

http://php.net/manual/en/language.oop5.decon.php

it is not necessary but generally that's good practice. I personally, when wish to boost error-checking mechanism, you $con->close() for almost each function. e.g:

if($stmt = $db->prepare($statment))
{
    if($db->bind_param($str, $param1, $param2))
    {
        // the rest of the code and error checking
    }
    else
    }
       $db->close();
    }
}
else
{ 
 $db->close();
}

This makes OOP necessary. Since you can simply write function doing this automatically with many other security checks added. codeIgniter as a framework has nice DB connectors whith superb security at a basic general level.