Edit report at https://bugs.php.net/bug.php?id=65723&edit=1
ID: 65723
Updated by: ahar...@php.net
Reported by: m dot banaszek at smartmedia dot com dot pl
Summary: Memory limit of string
-Status: Open
+Status: Not a bug
Type: Bug
-Package: Systems problem
+Package: Scripting Engine problem
Operating System: Windows 8
PHP Version: Irrelevant
Block user comment: N
Private report: N
New Comment:
There are some issues with your test: in its default "string" mode, memory
usage
never actually increases. If I change it to "array" mode, it behaves how the
manual says it will â 81 iterations succeed ($strb is 10,000,000 bytes in
size,
and the effective memory limit is 838,860,800 bytes), and then the script
errors
out with an out of memory error (there are 810,000,000 bytes in the array, plus
overhead for the array itself, plus $strb, plus general overhead). Bear in mind
that the memory limit applies to the entire runtime, not individual variables.
A simpler, clearer test is this:
<?php
ini_set('memory_limit', '800M');
$buffer = '';
while (true) {
$buffer .= str_repeat(' ', 10000000);
printf("Length of buffer: %d\nMemory usage: %d\n", strlen($buffer),
memory_get_usage());
}
?>
In short, this behaves as expected and documented.
Previous Comments:
------------------------------------------------------------------------
[2013-09-20 11:24:10] m dot banaszek at smartmedia dot com dot pl
Description:
------------
The PHP manual now states, that strings are limited to 2GB. However in test
script, I specify a memory limit to 800MB. I wrote a PHP application where
memory
usage is growing over time. Unfortunately the size of a single string variable
doesn't exceed memory limit of 300-400MB and my test stops. Testing my script
on
5.4.17,18,19 and 5.3.10 of PHP versions, but any of this versions don't
supported my memory limit or 2GB memory.
Test script:
---------------
<?php
ini_set('memory_limit', '800M');
$string = '1234567890';
$strb = '';
for ($i = 0; $i < 1000000; $i++)
$strb .= $string;
$arr = array();
$i = 0;
$testType = 'string'; //'array'
while (1) {
$i++;
if ('string' == $testType) {
error_log((strlen($string) / 1000000) . ' - ' .
(memory_get_usage() / 1000000));
} else {
$arr[] = $strb . $i;
error_log((strlen($string) / 1000000) . ' - ' .
(memory_get_usage() / 1000000));
}
error_log((count($arr)) . ' - ' . (memory_get_usage() / 1000000)); }
Expected result:
----------------
Memory usage grow to about 800MB.
Actual result:
--------------
Memory error of 300-400MB. So the memory usage does not continually grow to
800MB.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=65723&edit=1
