How to run a php function after certain time without using cron

Question

I have a block of code and want to run it after certain time intervals, say after every 3 seconds. If I get required result it should die otherwise another request will be sent after 3 seconds. Any idea to do it with php.

Thanks in advance for any help

Answer 1

You can sleep in a loop:

while (true) {
    $result = doSomething;
    if (resultIsGood) {
        break;
    }
    sleep(3);
}

If you don't want to keep the browser waiting, you can look up ignore_user_abort() solutions on Google.

Answer 2

If what you want to execute MySQL queries (and nothing else), maybe using the MySQL event scheduler could fit your need:
http://dev.mysql.md/doc/refman/5.5/en/events-overview.html