From: frode dot guldberg at exense dot com
Operating system: Windows XP
PHP version: 5.2.5
PHP Bug Type: Performance problem
Bug description: Huge memory usage
Description:
------------
In a for-loop I concatenate two strings. If I at the same time fill a
relatively small array, I get a huge memory consumption. This only happens
if I concatenate the two strings using '.'. If I use '.=' the memory usage
is as expected.
Reproduce code:
---------------
<?php
$string = str_repeat('This is a teststring.', 50);
echo 'Length: '.strlen($string).'<br>';
echo 'Memory Before:'.memory_get_usage(true).'<br>';
for($i = 1; $i <= 2000; $i++)
{
// $newstring .= $string; //This uses an expected amount of mem.
$newstring = $newstring . $string; //This uses very much mem.
for($j = 1; $j <= 10; $j++)
{
$array[] = 'test';
}
}
echo 'Memory After:'.memory_get_usage(true).'<br>';
echo 'Total Length of String: '.strlen($newstring).'<br>';
?>
Expected result:
----------------
Length: 1050
Before:262144
After:4456448
Length: 2100000
Actual result:
--------------
Length: 1050
Before:262144
After:161742848
Length: 2100000
--
Edit bug report at http://bugs.php.net/?id=44069&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=44069&r=trysnapshot44
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=44069&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=44069&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=44069&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=44069&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=44069&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=44069&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=44069&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=44069&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=44069&r=support
Expected behavior: http://bugs.php.net/fix.php?id=44069&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=44069&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=44069&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=44069&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=44069&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=44069&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=44069&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=44069&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=44069&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=44069&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=44069&r=mysqlcfg
