Unserialize link

output

phinas@trogdor$ php unserialize-link-maybe.php 20
Attach 8 MB shared memory segment
Memory after my_array creation:   524288 -> 25427968 (+24903680 +23.75 MB, initial +24903680 +23.75 MB)
Memory used by serialized my_array 1st element: 335 B, used by serialized my_array: 3.26 MB, 10000 elements
Memory after       unset#001: 26214400 -> 26738688 ( +524288 +512 kB, initial  +524288 +512 kB)
Memory after       unset#003: 26738688 -> 27000832 ( +262144 +256 kB, initial  +786432 +768 kB)
Memory after       unset#004: 27000832 -> 26738688 ( -262144 -256 kB, initial  +524288 +512 kB)
Memory after       unset#005: 26738688 -> 27000832 ( +262144 +256 kB, initial  +786432 +768 kB)
Memory after       unset#006: 27000832 -> 27787264 ( +786432 +768 kB, initial +1572864 +1.5 MB)
Memory after       unset#007: 27787264 -> 28573696 ( +786432 +768 kB, initial +2359296 +2.25 MB)
Memory after       unset#008: 28573696 -> 29097984 ( +524288 +512 kB, initial +2883584 +2.75 MB)
Memory after       unset#009: 29097984 -> 29884416 ( +786432 +768 kB, initial +3670016 +3.5 MB)
Memory after       unset#010: 29884416 -> 30670848 ( +786432 +768 kB, initial +4456448 +4.25 MB)
Memory after       unset#011: 30670848 -> 31457280 ( +786432 +768 kB, initial +5242880 +5 MB)
Memory after       unset#013: 31457280 -> 31719424 ( +262144 +256 kB, initial +5505024 +5.25 MB)
Memory after       unset#015: 31719424 -> 32243712 ( +524288 +512 kB, initial +6029312 +5.75 MB)
Memory after       unset#017: 32243712 -> 32768000 ( +524288 +512 kB, initial +6553600 +6.25 MB)
Memory after       unset#018: 32768000 -> 33030144 ( +262144 +256 kB, initial +6815744 +6.5 MB)
Memory after       unset#019: 33030144 -> 33292288 ( +262144 +256 kB, initial +7077888 +6.75 MB)
Memory after       unset#020: 33292288 -> 33554432 ( +262144 +256 kB, initial +7340032 +7 MB)
Memory after      shm_remove: 33554432 -> 33292288 ( -262144 -256 kB, initial +7077888 +6.75 MB)
Defined variables: argc, argv, num_loops, shm_size, shm_key, shm_id, initial_memory_usage, prev_memory_usage, memory_usage, loop, k, i

unserialize-link-maybe.php

<?php

main($_SERVER['argc'], $_SERVER['argv']);

function main($argc, $argv) {
	if ( $argc > 1 ) {
		$num_loops = abs(intval($argv[1]));
	} else {
		$num_loops = 1;
	}

		$initial_memory_usage = 0;
		$prev_memory_usage    = 0;
		$memory_usage         = 0;
		$loop                 = 0;
		$initial_memory_usage = memory_get_usage(true);
		$prev_memory_usage    = $initial_memory_usage;
		
		for ($k = 1 ; $k <= 10000 ; $k++) {
			$my_array[$k] = array();
			for ($i = 0; $i < 12 ; $i++) {
				$my_array[$k]["item_".$i] = "value_".$i;
			}
		}
		print_memory_usage("my_array creation", $initial_memory_usage, $memory_usage, $prev_memory_usage);
		print_array_size($my_array, "my_array");
		
		// Reset memory usage after my_array allocation
		$initial_memory_usage = memory_get_usage(true);
		$prev_memory_usage    = $initial_memory_usage;
		$memory_usage         = $initial_memory_usage;
		
				
		// This loop seems to leak memory...
		for ($loop = 1 ; $loop <= $num_loops ; $loop++) {
			
			unserialize_test($my_array, true);
			
			print_memory_usage(sprintf('Loop#%03d', $loop), $initial_memory_usage, $memory_usage, $prev_memory_usage);
			
	    }
		// debug_zval_dump($my_array);
		unset($my_array);
		print_memory_usage('unset', $initial_memory_usage, $memory_usage, $prev_memory_usage);
		printf("Defined variables: %s\n", implode(", ", array_keys(get_defined_vars())));
		
	
}
/* ------------------------------ END MAIN --------------------------------------------------------------*/

function unserialize_test(&$my_array, $change_values) {
	$new_array = unserialize(serialize($my_array));
	
	if ( $change_values ) {
		/*
		 * Change values in new_array (to defeat copy-on-write)
		*/
		for ($k = 1 ; $k <= 10000 ; $k++) {
			for ($i = 0; $i < 12 ; $i++) {
				$new_array[$k]["item_".$i] = "VALUE_".$i;
			}
		}
	}
		
	// print_memory_usage(sprintf('set#%03d', $loop), $initial_memory_usage, $memory_usage, $prev_memory_usage);
	// debug_zval_dump($new_array);
	unset($new_array);
}

function print_memory_usage($function_name, $initial_memory_usage, &$memory_usage, &$prev_memory_usage) {
	usleep(500 * 1000); // Sleep to let GC run
    $memory_usage = memory_get_usage(true);
    if ( $memory_usage != $prev_memory_usage) {
    	printf("Memory after %15s: %8d -> %8d (%+8d %s, initial %+8d %s)\n"
    			, $function_name
    			, $prev_memory_usage
    			, $memory_usage
    			, ($memory_usage - $prev_memory_usage)
    			, format_delta($memory_usage - $prev_memory_usage)
    			, ($memory_usage - $initial_memory_usage)
    			, format_delta($memory_usage - $initial_memory_usage)
    	);
    	$prev_memory_usage = $memory_usage;
    }
}

function print_array_size($array, $array_name) {
	printf("Memory used by serialized %s 1st element: %s, used by serialized %s: %s, %d elements\n"
			, $array_name
			, (count($array) > 0)?format_size(php_sizeof(reset($array))):format_size(0)
			, $array_name
			, format_size(php_sizeof($array))
			, count($array));
}
    
    function php_sizeof($object) {
    	return (strlen(serialize($object)));
    }
    
    /**
     * Return a string formatted size from a given size in bytes.
     *
     * @param int $bytes quantity to format
     * @return string
     */
    function format_size($bytes, $precision = 2) {
    	$units = array(' B', ' kB', ' MB', ' GB', ' TB', ' PB');
    
    	$bytes = max($bytes, 0);
    	$pow = floor(($bytes ? log($bytes) : 0) / log(1024));
    	$pow = min($pow, count($units) - 1);
    	$bytes /= pow(1024, $pow);
    
    	return round($bytes, $precision) . $units[$pow];
    }
    
    /**
     * Return a string formatted delta from a given size in bytes.
     *
     * @param unknown $size
     * @return string
     */
    function format_delta($bytes, $precision = 2) {
    	$sign = ($bytes < 0)?'-':'+';
    	return $sign . format_size(abs($bytes), $precision);
    }