ID: 13300
User updated by: [EMAIL PROTECTED]
Reported By: [EMAIL PROTECTED]
Status: Open
Bug Type: Session related
Operating System: Linux
PHP Version: 4.0.5
New Comment:

For now, I have found a workaround in the case of storing session data in MySQL.

All you simply need to do in your write handler function is to issue a WRITE locking 
query before the one that inserts/updates the session record and an unlocking query 
afterwards. This means that the SELECT query issued from the session read handler in 
the page that was re-directed to happens, it is queued until the session write from 
the previous page is finished.

So, instead of simply:

REPLACE INTO table_name (sess_id, mod_date, data) VALUES ('$sess_id', NOW(), 
'$value');

You will have:

LOCK TABLES table_name WRITE;
REPLACE INTO table_name (sess_id, mod_date, data) VALUES ('$sess_id', NOW(), 
'$value');
UNLOCK TABLES;

I'm sure this will seem obvious to some people, but I still think the current 
methodology is flawed.

Previous Comments:
------------------------------------------------------------------------

[2001-09-14 07:55:43] [EMAIL PROTECTED]

I am experiencing the effects of bug #12968 too. However, it's not really a bug (as in 
there is something malfunctioning), but rather a BIG design flaw. The whole thing 
centres around the behaviour mentioned in the manual for the function 
session_set_save_handler():

"The 'write' handler is not executed until after the output stream is closed."

Because the output buffer is sent before the write handler is called, when the client 
browser is on a fast network connection (i.e. an internal LAN in my case too) it 
recieves the output and acts upon the 302 redirect HTTP header before the write 
handler has finished executing. However, in this case, because we are using MySQL, the 
session write handler function takes some time - especially so when your MySQL 
database is on a seperate host to the web server. This results in the page which is 
being re-directed to executing in it's entirity (including the session read/write 
handlers) before the original session write function finishes.

This is a MAJOR design flaw (nothing should ever rely upon the speed of a client 
connection), and I move that this behaviour be changed immediately. The session write 
handler should be called before the output buffer is sent, but still only after the 
script has finished executing.

------------------------------------------------------------------------



Edit this bug report at http://bugs.php.net/?id=13300&edit=1


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