ID: 44069
Updated by: [EMAIL PROTECTED]
-Summary: Huge memory usage with concatenation using . instead
of .=
Reported By: frode dot guldberg at exense dot com
-Status: Assigned
+Status: Closed
Bug Type: Performance problem
Operating System: *
PHP Version: 5.2.5
Assigned To: dmitry
New Comment:
This bug has been fixed in CVS.
Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
Thank you for the report, and for helping us make PHP better.
Previous Comments:
------------------------------------------------------------------------
[2008-02-13 18:25:44] [EMAIL PROTECTED]
Dmitry, can you check this out please? The example script kills my
machine totally if I don't use the .= :)
------------------------------------------------------------------------
[2008-02-07 13:39:05] frode dot guldberg at exense dot com
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 this bug report at http://bugs.php.net/?id=44069&edit=1
