How much data can 1 session variable hold?

Tea_J

I was wondering if it's alrite to store a whole page in one session variable..

Here's what i have:


<?

session_start();

$_SESSION['page'] = <<<HTML

//web page source code here.. and $variables are insterted accordingly

HTML;
?>

After above page, my other pages can call the session variable and echo it !! no need to keep pre formatting etc etc in html.. also started using this method for tables that i keep recalling.

it seems to work just fine.. but would like to know what you guys think of this method..

I just discovered the above technique this morning and it has made my work soo much easier..... i hope it's alrite to go on using this. but please dont be afraid to burst my bubble.. i dont bite. 🙂

Tea

leatherback

Why would you even want to do this?

Personally I feel that you are creating a lot of overhead and producing unneeded data transfers. But I may be wrong

justsomeone

I wouldn't imagine that it would scale very well. More and more active users on your site, chewing up more and more RAM in large session variables could bring your server to its knees.

It could also cause problems in a clustered environment.

You would want to run some serious load tests.

Tea_J

ok.. so what do you think is the efficient adn acceptable limit?

I know it depends on the resources, hardware (of server), and how many users.. but typically, what do you guys think is a good limit? I dont think 50kb in a session variable would hurt that much. hmm.. thnking...

justsomeone

there's no generic answer other than "as much as you need and as little as you can get away with".

If you're building an intranet solution which will be used by no more than 10-20 simultaneous users, you are free to hold much more in memory. If you're building a popular website with hundreds/thousands of simultaneous users, you may not have that luxury.

If you have tons of budget, you can throw hardware at the problem to make it go away. If you need to squeeze the most out of few resources, you need to be more careful.

Calculate your likely loads, and test against 2-3 times that many.

Tea_J

understood.. but like i said.. what do you think? 🙂

say.. a 100kb cap on a session variable? heck.. the web page it's on would probably be heavier.. taking up more resources per user....

Another way of lookinng at it is, on a typical server, when all is running, there is like at least 100MB or so of RAM left.. so if you do the unthinkable, like hold a 1 MB uploaded file in a session variable, you're good to hold about 80-90 of those without endangering your server...

me thinks... me feel is right.. but me could be wrong. 🙂

justsomeone

Personally, I tend to keep very little in session variables.

Originally, I just held a session ID and I went to a database for everything else. That just makes the db the bottleneck, so I added a few commonly used pieces of info there - username, real name, permissions, detail like that. No more than about 100 bytes.

Bu that's just my way - it may not be the best in the world for every application 🙂

Tea_J

lol. yep

so.. anyone else wana say something about this issue? Or are ya'll chicken!? hehehehe

leatherback

Not chicken. Just not knowledgable on the topic.

I tend to have 2-5 variables, integers and short strings, in my sessions. I really do not see the need to do anything else. I have a base include called getpage, which will get the basic page-setup and content based on pagetype and page id. So.. I would not use the session.

And again.. If the session is in the users' cookie, which happens, as far as I know, you have a big problem with passing the info up and down the line all the time. But again. Your choice.

Tea_J

I tend to have 2-5 variables, integers and short strings, in my sessions. I really do not see the need to do anything else. I have a base include called getpage, which will get the basic page-setup and content based on pagetype and page id. So.. I would not use the session.

where do you store the form variables for safe keeping then? (forms with at least 20 fields) ..ya know.. to make sure that the form data is safely kept, in case user needs to go back and forth thru pages, etc... to cookies? temporary database table? (NOOOO!!! lol)

leatherback

I do not keep them.
I echo the form values back into the form if there are errors. Else I process them. Why would I want to keep them? I have a database for storing info. If I need them, I retrieve them from there. Why bother with something a user can temper with?

Tea_J

I do not keep them.
I echo the form values back into the form if there are errors. Else I process them. Why would I want to keep them? I have a database for storing info. If I need them, I retrieve them from there. Why bother with something a user can temper with?

well, coz echoing back is ok.. but what if the user hits the BROWSER BACK button.. then it's not a form submit.. then you loose data.. i've received many complains regarding that form behavior.. hence keeping them in the session to make sure user dont get his time filling the form up wasted..

leatherback

Hm.. Yeah, well, what can I say. The user shouldn't use the back-button. Why would they? If your web-layout is sound, they should not have to: As I said: When hte input is incorrect, you echo out the form, with their submitted values. Otherwise you store the info into a database.

Then, you log them into the system usin one or two session vars. When they use the back button, they are logged in, and their data get's retrieved from the database. No problem whatsoever.

autocolismo

ever eard of css?

leatherback

autocolismo wrote:
ever eard of css?

Yes, but what is the relevance to this topic?

autocolismo

After above page, my other pages can call the session variable and echo it !! no need to keep pre formatting etc etc in html.. also started using this method for tables that i keep recalling.

...

Tea_J

Yes, but what is the relevance to this topic?

lol

🙂

Hm.. Yeah, well, what can I say. The user shouldn't use the back-button.

you'd be surprised.. i know lots of people.. even myself.. for many reasons..

another thing... what if your server/script/their internet connection or whatever times out as soon as it has left the first page??? it happens a lot.. oh well, each to his own i guess. 🙂

hmm... does anyone else here use session variables, or whatever to temporary keep form data?

leatherback

Tea_J wrote:
you'd be surprised.. i know lots of people.. even myself.. for many reasons..

another thing... what if your server/script/their internet connection or whatever times out as soon as it has left the first page??? it happens a lot.. oh well, each to his own i guess. 🙂

Hi,

Did you read the rest of that post? If the user passes the right info, it is processed, thus available to whichever page is to be loaded. Through a back or forward motion. If the page times out, and the data do not get passed to the server for processing, also your session will be empty.

Anyway. Please. Go ahead and place all var's in the session, if you feel that is the best.

Tea_J

If the page times out, and the data do not get passed to the server for processing, also your session will be empty.

yup. you're right.. 🙂 but.. what if half of the page loads?! then surely you'll have to press BACK.. heheh. i dunno.. just exploring...

Anyway. Please. Go ahead and place all var's in the session, if you feel that is the best.

umm.. that's what im doing now.. 🙁 just wanted to know how other people like you feel about it.. andif there are other BETTER programmers than I out there that does this.. surely you dont.. hehe.

thanks for your advises though.. very well noted

taveira

I'm no programming guru, maybe I'm not even better or near your programming skills, but one thing I know is that the method you're using is just stupid and non-logical!

SESSION variables are, as the name indicates, for storing SESSION related stuff, like session id, username, basic stuff that you later can relate to some key in a table in a database!

If you want to save "coding work" just put the recurrent code you need (tables, <head> sections, whatever...) in a file and include it in your code when you need it!

You say even 1MB wouldn't be much... if you have broadband connection... but when you're web programming you must think on everybody: the ones that have broadband connection or 33.6K modem!
And don't forget: for you 100Kb may not be much, but if it were 100bytes it would be even better!

Sorry the extension, but I could'nt cope with such non-logical thinking of yours, because programming os just that: LOGIC!