Function for getting size of any PHP variable in bytes.
It must be more accurate tool to calculate total size of PHP variable than memory_get_usage()
, but it has restrictions.
var_sizeof()
with var_class_sizeof()
uses FFI to access internal structures of PHP variables.
It calculates the size of internal structures such as zval
, _zend_array
, _zend_object
, etc., as well as additional allocated memory for them.
It doesn't take into calculate the memory of handlers/functions/etc.
- PHP >= 7.4 (with FFI)
- Linux(x86_64) / Darwin(x86_64)
composer install mrsuh/php-var-sizeof
int var_sizeof(mixed $var);
int var_class_sizeof(mixed $var);
<?php
require_once __DIR__ . '/vendor/autoload.php';
$int = 1;
printf("variable \$int size: %d bytes\n", var_sizeof($int));
$array = array_fill(0, 100, $a);
printf("variable \$array size: %d bytes\n", var_sizeof($array));
$object = new \stdClass();
printf("variable \$object size: %d bytes\n", var_sizeof($object));
printf("class \$object size: %d bytes\n", var_class_sizeof($object));
PHP 8.1.2 Linux(x86_64)
type | var_sizeof(bytes) | memory_get_usage(bytes) |
---|---|---|
NULL | 16 | 0 |
boolean(true) | 16 | 0 |
integer(1) | 16 | 0 |
double(1.5) | 16 | 0 |
string("hello world") | 27 | 40 |
resource | 48 | 416 |
callable | 72 | 384 |
array(count: 0, list: true) | 336 | 0 |
array(count: 100, list: true) | 2,128 | 8,248 |
array(count: 1,000, list: true) | 16,464 | 36,920 |
array(count: 10,000, list: true) | 262,224 | 528,440 |
array(count: 100, list: false) | 5,192 | 8,248 |
array(count: 1,000, list: false) | 41,032 | 41,016 |
array(count: 10,000, list: false) | 655,432 | 655,416 |
EmptyClass{} | 72 | 40 |
ClassWithArray{"array(count: 0, list: true)"} | 408 | 56 |
ClassWithArray{"array(count: 100, list: true)"} | 2,200 | 8,304 |
ClassWithArray{"array(count: 1,000, list: true)"} | 16,536 | 36,976 |
ClassWithArray{"array(count: 10,000, list: true)"} | 262,296 | 528,496 |
ClassWithObject{"EmptyClass{}"} | 144 | 96 |
type | var_class_sizeof(bytes) | var_sizeof(bytes) | memory_get_usage(bytes) |
---|---|---|---|
EmptyClass{} | 1,362 | 72 | 40 |
ClassWithArray{"array(count: 0, list: true)"} | 1,494 | 408 | 56 |
ClassWithArray{"array(count: 100, list: true)"} | 1,494 | 2,200 | 8,304 |
ClassWithArray{"array(count: 1,000, list: true)"} | 1,494 | 16,536 | 36,976 |
ClassWithArray{"array(count: 10,000, list: true)"} | 1,494 | 262,296 | 528,496 |
ClassWithObject{"EmptyClass{}"} | 1,495 | 144 | 96 |
- objects - you need to use
var_sizeof()
withvar_class_sizeof()
to calculate total variable size because of class structure load once for a one class var_class_sizeof()
- function calculates current/parent class properties sizes only. It doesn't calculate the sizes of the functions in the class- resource/callable -
var_sizeof()
calculates only major structures
git clone git@github.com:mrsuh/php-var-sizeof.git && cd php-var-sizeof
composer install
docker build -t image-php-var-sizeof .
docker run -it --rm --name my-running-script -v "$PWD":/app image-php-var-sizeof php bin/render-table.php
cd php-src
./buildconf
./configure
cd ..
make