#25853 [Opn->Bgs]: CLI application not freeing used memory even with unset

ID: 25853 Updated by: sniper@php.net Reported By: morgan at mindviz dot com -Status: Open +Status: Bogus Bug Type: CGI related Operating System: RedHat Linux 8.0 PHP Version: 4.3.3 New Comment: unset() does not free any memory. This is by design. Previous Comments: ------------------------------------------------------------------------ [2003-10-13 13:17:25] morgan at mindviz dot com Description: ------------ Basically I'm writing a php-CLI server application that will never exit unlike an apache process. I have been attempting to find out why slowly but surely the memory usage of my CLI app steadily goes up until it has exhausted all my available memory. The server app will read in large data sets at times and then attempts to free those with the unset function. With further inspection it seems that even though unset is called the script still has a hold on or uses the allocated memory and never returns it to the system. The code below is a small script that I put together to show the issue I am seeing, it is quite easy to reproduce the problem. As with my server application if the script below was run forever and the max value of $z in the loop was set extremely high it would run until all the system's memory was used up, since unset is not actually returning any of the used memory for the test_array back to the system. Reproduce code: --------------- #!/root/php-4.3.3/php -n <?php $my_pid = getmypid(); echo "GOT PID: ".ps -eo %mem,rss,pid | grep $my_pid."\n"; for($z = 0; $z < 10; $z++) { $test_array = array(); // Build a Test 5x(1000*$z) array, will show incremental mem usage and after unset // line will test_array's memory will not be free'd for($i = 0; $i < 5; $i++) { for($j = 0; $j < 1000*$z; $j++) { $test_array[$i][$j] = "testing $i $j\n"; } } echo "$z: MEMORY USAGE BEFORE UNSET ( % KB PID ) : ".`ps -eo %mem,rss,pid | grep $my_pid`; unset($test_var); echo "$z: MEMORY USAGE AFTER UNSET ( % KB PID ) : ".`ps -eo %mem,rss,pid | grep $my_pid`."\n"; } exit; ?> Expected result: ---------------- GOT PID: 0.1 1524 3178 0: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.1 1532 3178 0: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 1: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.2 2132 3178 1: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 2: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.3 2740 3178 2: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 3: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.3 3368 3178 3: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 4: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.4 3952 3178 4: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 5: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.5 4620 3178 5: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 6: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.5 5204 3178 6: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 7: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.6 5792 3178 7: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 8: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.7 6376 3178 8: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 9: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.7 7124 3178 9: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1524 3178 Actual result: -------------- GOT PID: 0.1 1524 3178 0: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.1 1532 3178 0: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.1 1532 3178 1: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.2 2132 3178 1: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.2 2132 3178 2: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.3 2740 3178 2: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.3 2740 3178 3: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.3 3368 3178 3: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.3 3368 3178 4: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.4 3952 3178 4: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.4 3952 3178 5: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.5 4620 3178 5: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.5 4620 3178 6: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.5 5204 3178 6: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.5 5204 3178 7: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.6 5792 3178 7: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.6 5792 3178 8: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.7 6376 3178 8: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.7 6376 3178 9: MEMORY USAGE BEFORE UNSET ( % KB PID ) : 0.7 7124 3178 9: MEMORY USAGE AFTER UNSET ( % KB PID ) : 0.7 7124 3178 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=25853&edit=1