Edit report at http://bugs.php.net/bug.php?id=52109&edit=1
ID: 52109
User updated by: smacky86 at gmail dot com
Reported by: smacky86 at gmail dot com
Summary: session_start / session_write_close memory leak
Status: Bogus
Type: Bug
Package: Session related
Operating System: Linux
PHP Version: 5.3.2
New Comment:
In my case I start a database synchronization from a website, send the
job to the background, and show the actual result to the user.
e.g.:
if (isset($_POST["user_clicked_on_the_synch_button"]))
{
header("Location: ?result_page");
header("Content-length: 0");
header("Connection: close");
session_write_close();
usleep(100);
// at this point the browser goes to the result page, and we can start
the synchronization process in the background
synch();
// this event handler is called after every synchronized product
function onSynchEvent()
{
// here i need to save the actual state of the synch process
session_start();
$_SESSION["blah"]++;
session_write_close();
}
}
On the result page I can check this session variable with periodic ajax
requests. The session has to be closed due to the file lock.
This is why I have to call session start/close multiple times.
Since the browser is already detached, it throws the "cannot start
session, headers already sent" errors, but even then the data is stored
in session.
Previous Comments:
------------------------------------------------------------------------
[2010-07-03 11:52:28] [email protected]
That is expected. You might have sessions with different session names
and keeping a list of them is a source of more trouble than simply
sending them out in the correct order and letting the browser decide
which to keep. Especially as usually no application doe multiple
session_start) calls.
------------------------------------------------------------------------
[2010-07-03 04:06:24] smacky86 at gmail dot com
Now I was able to test this case with a fresh new setup, now really
v5.3.2 (the previous was 5.2.9, but I opend the ticket as 5.3.2).
The problem without Suhosin or any other extension doesn't appear, so
the first question is solved.
But I observed something: the header of the HTTP response contains a lot
of Set-Cookie line, one for each session_start() call.
I don't think it's the right way it should work.
------------------------------------------------------------------------
[2010-06-21 07:19:26] [email protected]
I forgot to include, did you try to disable the Zend allocator
(USE_ZEND_ALLOC)?
------------------------------------------------------------------------
[2010-06-21 07:07:56] [email protected]
We don't support PHP patched with 3rd party patches like Suhosin, what
is the results without, and what does valgrind give you? Should show if
there is a real leak
------------------------------------------------------------------------
[2010-06-17 15:49:23] smacky86 at gmail dot com
Description:
------------
session_start() and session_write_close() don't free unused memory. When
they are called multiple times, the memory usage reported by
memory_get_usage() constantly grows.
The session data is stored in files, ini settings are default.
# php -v
PHP 5.2.9 (cli) (built: Sep 1 2009 11:43:38)
Copyright (c) 1997-2009 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2009 Zend Technologies
with Suhosin v0.9.31, Copyright (c) 2007-2010, by SektionEins GmbH
Test script:
---------------
session_start();
$_SESSION["foo"] = str_repeat("bar", 5000);
session_write_close();
$memory_before = round(memory_get_usage() / 1024, 2) . "KB";
for ($i=0; $i<1000; $i++)
{
session_start();
session_write_close();
}
$memory_after = round(memory_get_usage() / 1024, 2) . "KB";
echo "Before: " . $memory_before . "\n";
echo "After: " . $memory_after;
Expected result:
----------------
Before: 88.34KB
After: 88.34KB
(or something small amount)
Actual result:
--------------
Before: 88.34KB
After: 19906.61K
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/bug.php?id=52109&edit=1
