From: mail at milianw dot de
Operating system: linux, windows
PHP version: 5.2.6
PHP Bug Type: Performance problem
Bug description: memory leak with unset(array)
Description:
------------
When you setup an array and unset() it afterwards, not all memory is
freed. I've run the code below on various PHP versions, including 5.2.6
(via Xampp) on Linux and Windows and always get output like:
startup: 64296
array setup: 13789672
unsetted array: 129284
The end value is more than twice as large as the start value.
Also interestingly is that low values in the for loop [e.g. for($i = 0; $i
< 1; ++$i)] result in outputs like
startup: 64296
array setup: 64864
unsetted array: 64864
Could it be that unset() relies on the Garbage Collector to do the work
instead of really destroying the variables? But then I find it strange that
even if I put a sleep(10) after the unset I still get the same outputs for
"unsetted array".
Reproduce code:
---------------
<?php
echo "startup: ".memory_get_usage()."\n";
$array = array();
for ($i = 0; $i < 100000; ++$i) {
$array[] = 'foobar';
}
echo "array setup: ".memory_get_usage()."\n";
unset($array);
echo "unsetted array: ".memory_get_usage()."\n";
Expected result:
----------------
My expectations would be that the value reported at the end would be
nearly equal to the startup value.
Additionally a call to unset() should (imo) not rely on the GC but do the
deleting itself instantaneously.
NOTE: I've seen http://bugs.php.net/bug.php?id=41713 which tells a similar
story, but it should be fixed as far as the bug report tells. Additionally
it was Windows only yet I spotted the described behaviour first on a Linux
machine.
--
Edit bug report at http://bugs.php.net/?id=45954&edit=1
--
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=45954&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=45954&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=45954&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=45954&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=45954&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=45954&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=45954&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=45954&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=45954&r=support
Expected behavior: http://bugs.php.net/fix.php?id=45954&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=45954&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=45954&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=45954&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=45954&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=45954&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=45954&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=45954&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=45954&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=45954&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=45954&r=mysqlcfg
