Description:
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---
From manual page: http://www.php.net/simplexmlelement.xpath
---


Test script:
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<?php
$sxe = NULL; $nodes = NULL;
print("Without call to xpath method : " . PHP_EOL);
print("Memory before SXE  : " . memory_get_usage() . PHP_EOL);
$sxe = new SimpleXMLElement("large_file.xml", 0, TRUE);
$sxe = NULL; $nodes = NULL;
print("Memory after freed memory : " . memory_get_usage() . PHP_EOL . PHP_EOL);

$sxe = NULL; $nodes = NULL;
print("Calling xpath method : " . PHP_EOL);
print("Memory before SXE  : " . memory_get_usage() . PHP_EOL);
$sxe = new SimpleXMLElement("large_file.xml", 0, TRUE);
$nodes = $sxe->xpath('/ITEMS/ITEM');
$sxe = NULL; $nodes = NULL;
print("Memory after freed memory : " . memory_get_usage() . PHP_EOL . PHP_EOL);

// short sleep, time to launch 'ps aux'
sleep(10);
?>


Expected result:
----------------
When I unset (or set to NULL) the result of the Xpath() method ($nodes in the example), I expect memory will be completly freed. It's not the case. 

I tried, to recursively unset each element from $nodes and I got the same result. 



Actual result:
--------------
Result of the test script :

Without call to xpath method : 
Memory before SXE  : 625736
Memory after freed memory : 625904

Calling xpath method : 
Memory before SXE  : 625904
Memory after freed memory : 1608944


memory_get_usage says that few kilos octets of memory are still used, but in reality several thousand mega octets are still used.

# ps aux | grep test.php

me  28859 83.4 48.3 *1119908* *996056* pts/3  S+   15:30   0:08 /bin/php test.php