It is exactly what you need. And you can lower the sleep time, I think 1
or 2 seconds are just enough.

Glenn Gasner wrote:
> The php.net documentation for the sleep and usleep functions has me
> confused. I'm using shared hosting and I need to email my whole mailing
> list while not clogging the shared mail server. What I'm trying to do is
> put a pause between each email sent (like 10 seconds) so I can set it up to
> send a thousand (or whatever) messages without manually putting time between
> batches. My guess is that I should put a line with sleep(10); inside the
> mail sending loop so that it pauses between notes. However, the Jan-17 note
> on the usleep function mentions that these kinds of loops can consume 100%
> of CPU while running. The Jan-29 note on the time() function says that
> sleep uses way less CPU than wait(). I don't know how to test CPU usage of
> any PHP function. Is sleep() really so CPU intensive that I should avoid
> it, is there a better function to use, or is it exactly what I need and
> it'll be no problem even on a shared server?
>
> Thanks!
> Glenn Gasner
> glenn at perex dot com
>