ID: 13300
Updated by: yohgaki
Reported By: [EMAIL PROTECTED]
Old Status: Open
Status: Closed
Bug Type: Session related
Operating System: Linux
PHP Version: 4.0.5
New Comment:
If you are using database and worry about cases like this, lock should be used.
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Yasuo Ohgaki
Previous Comments:
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[2001-09-14 10:07:39] [EMAIL PROTECTED]
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.
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[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.
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Edit this bug report at http://bugs.php.net/?id=13300&edit=1
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