Session cookie read-write speed

[FlashHeart]

Hi There,

Maybe someone knows....

I have a PHP site that makes extensive use of the session cookie. I'm wondering how effiecient reading and writing from the session cookie really is? After all it's just a text file with no index. There are some instances where I've saved some MySQL query field value into the session cookie to save me having the re-run the query each time the user returns to the page, but if the query result is in the query cache then would it be faster to re-run the query (and hence get the result from the query cache) or retreive the value from the session cookie???

Cheers!

Dex.

[AstroTeg]

Someone correct me if I'm wrong since I'm not familiar with the inner workings of PHP, but I believe the session is loaded when you start the session. The session data is read from disk and the data stored in the necessary variables. As far as disk reading goes, thats it. You can call on those variables as many times as you like since they're in memory. Either on session close or the end of the PHP processing, the session file will get rewritten with the new session data.

If you have gobs of data, then maybe storing it in a database would make more sense. Or if you needed portability between systems and sessions (say an ASP based site and PHP site needed access to the session data).

I'd say the ultimate test would be to try both approaches and use microtime() and see which is quicker. I'd think session reading would be pretty quick since it doesn't need to interrogate a database server.