Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:49885
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <73.09.01054.7EC0EAC4@pb1.pair.com>
To: internals@lists.php.net
Date: Thu, 7 Oct 2010 14:09:11 -0400
Lines: 20
Subject: stat functions do each path component?
From: snicholnews@scottnichol.com ("Scott Nichol")

In comparing the performance of PHP 5.2.5 file_exists calls versus C stat calls, I discovered via Windows sysinternals 
ProcessMonitor that PHP seems to do a stat on each component of a file path.  For example, 
file_exists("e:\\wamp\\www\\ra-v2\\system\\application\\libraries\\MY_Controller.php") appears to stat "E:\wamp", "E:\wamp\www", 
etc., finally getting to the file.  That compares to doing _stat64 of 
"e:\\wamp\\www\\ra-v2\\system\\application\\libraries\\MY_Controller.php" in C, which just does the stat on the file.  The timings 
from my tests show the C app finishing in about one-seventh the time, which is what I would expect from the PHP code doing seven 
times as many stat calls.

Assuming my inference about all the stat calls is correct, is there a rationale for this?  If the PHP app I am working on made just 
a couple of file_exists calls, I would not bother to ask, but it uses the CodeIgniter framework which is doing >100 file_exists 
calls for each page being accessed, so the affect is very noticeable.

FYI, I poked around the PHP SVN web interface for a while and found php_check_open_basedir_ex called in plain_wrapper.c, which I 
suspect causes the calls, but ran out of steam before confirming the cause of the behavior.

TIA
-- 
Scott Nichol