database vs. session speed

mburbulla

in my application i need some data from the database - every request. it would be perfect to use a (centralized) caching mechanism for this data but as far as i know, all i can do in php is storing this data in the session. this data gets serialized to disk and de-serialized every request.

can anyone tell me if it is better in general to get the data from the database every request or store it in the session? the database is on the same machine as the php-server (so no tcp/ip overhead) and data consistency is not an issue.

thanks,
martin

nnichols

If the data is used in every page from session start to session end then use the session, otherwise get it from the db each time.

Personally I would ALWAYS retrieve the data from the db as I ALWAYS use a db for my session handling as flat files lack flexibility and are slow.

Only my opinion and other experienced developers may disagree, but you should keep your use of session variables to an absolute minimum.

Hope this helps 😉

mattr

DB-stored sessions are often adventageous -- for example if you have multiple web servers you can't use web server session space for storage.

adavis

Can you tell me about what you mean when you say

I ALWAYS use a db for my session handling

I have just starting working on my first stab at protecting a group of scripts. My user data is stored in a mySQL db and I'm using sessions, but some of this terminology is new to me.

Thanks.

nnichols

Read this -

http://www.php.net/manual/en/function.session-set-save-handler.php

It should give you an idea of what I was talking about. If you search on Google after reading this page of the manual you will find lots of examples using custom session handlers.

Hope this helps 😉

Edit: read this tutorial - http://www.tek-tips.com/gfaqs.cfm/pid/434/fid/2037