如何将一个非常长的内存密集型循环拆分为更小的块

Question

I have quite a long, memory intensive loop. I can't run it in one go because my server places a time limit for execution and or I run out of memory.

I want to split up this loop into smaller chunks.

I had an idea to split the loop into smaller chunks and then set a location header to reload the script with new starting conditions.

MY OLD SCRIPT (Pseudocode. I'm aware of the shortcomings below)

for($i=0;$i<1000;$i++)
{
  //FUNCTION
}

MY NEW SCRIPT

$start=$_GET['start'];
$end=$start+10;

for($i=$start;$i<$end;$i++;)
{
   //FUNCTION
}

header("Location:script.php?start=$end");

However, my new script runs successfully for a few iterations and then I get a server error "Too many redirects"

Is there a way around this? Can someone suggest a better strategy?

I'm on a shared server so I can't increase memory allocation or script execution time.

I'd like a PHP solution.

Thanks.

Answer 1

First off, without knowing what your doing inside the loop, it's hard to tell you the best approach to actually solving your issue. However, if you want to execute something that takes a really long time, my suggestion would be to set up a cron job and let it nail out little portions at a time. The script would log where it stops and the next time it starts up, it could read the log for where to start.

---

Edit: If you are dead set against cron, and you aren't too concerned about user experience, you could do this:

Let the page load similar to the cron job above. Except after so many seconds or iterations, stop the script. Display a refresh meta tag or javascript refresh. Do this until the task is done.