php automation for some tasks

i must call a php function every second

if i place it in a php file it runs a few times every call php file when calling an user

index.php

//code that i want run everysecond (or a few second)
 $bitsqlz = "SELECT id FROM tasks where id ='$todoid' and state='0';";
            $dataz = mysqli_query($con1,$bitsqlz); 
            while ($rowz= $dataz->fetch_assoc()) {
              $todoid= $rowz["id"];

//dont know how  but many users can come here even i set state = 0 below before all codes
// and same task runs a few times

$dataupd = mysqli_query($con1,"update todos set state=1 where id='$todoid'"); 

// proecess bla  bla bla...

}

or must i call it in server side ? (i dont know what is right way and how to make it runs in server side maybe linux can have a program for this. like schuled tasks. )

Answer

You can do an infinite while whith an sleep() of 1 second. But remember to increase the set_time_limit() and use “break” to end the loop.

And if you need to execute a PHP script from the server site on Linux, you can execute it typing “php index.php”.