CGI quick cleanup

I am using PHP for a system script to import TV listings to a database. It works well but creates 20,000 to 30,000 hash elements with various relationships and it *seems* to take exponentially longer for the script to actually stop running after it reaches the "exit" statement the more items there are. I also note that even though max execution time is set to zero and the script runs for a long time, I still get a max-execution error at 30 seconds after the script has been trying to exit (although the script runs for many minutes). 30 seconds is the timeout in the php.ini which I override with ini_set. I think this long shutdown time is PHP's per-page cleanup freeing all the objects, which is not so important if running as a CGI. Currently I am quitting with posix_kill(posix_getpid(),5) as it is pretty quick but I wondered if the per-page cleanup which is only important when running as an apache module could be disabled in cgi mode. Sam