He's using a BigIP hardware load balancer, so there's a good chance that he
can outrun the J2EE session replication mechanism between requests. This
isn't talked about a lot, but it happens.
Using Client variables stored in either cookies or a database shared by the
clustered servers eliminates potential "undefined in Session scope" errors
because ColdFusion either receives all Client variables in the request
(cookie) or ColdFusion waits until retrieval and parsing of the Client
variable has happened (database).
Note: before choosing to store Client variables in cookies (seductive
because it is the fastest technique by far), make sure you're not storing
any secure data in the Client scope. You wouldn't believe how many
developers forget this; you can spoof cookies that will take you right into
their admin sections. Also make sure the total size of your Client scope
won't bust any cookie size or quantity limitations.
Respectfully,
Adam Phillip Churvis
Member of Team Macromedia
Advanced Intensive Training:
* C# & ASP.NET for ColdFusion Developers
* ColdFusion MX Master Class
* Advanced Development with CFMX and SQL Server 2000
http://www.ColdFusionTraining.com
Download CommerceBlocks V2.1 and LoRCAT from
http://www.ProductivityEnhancement.com
The ColdFusion MX Bible is in bookstores now!
----- Original Message -----
From: "Calvin Ward" <[EMAIL PROTECTED]>
To: "CF-Talk" <[EMAIL PROTECTED]>
Sent: Wednesday, September 29, 2004 9:59 AM
Subject: RE: SESSION vs. CLIENT
> The short answer is that there can be need for both depending on the
situation.
>
> With CFMX Enterprise, you can leverage J2EE Sessions, that will allow you
to duplicate sessions across a cluster.
>
> Sessions have the advantage of being able to store complex data types, and
don't involve a call to a database.
>
>
> However, I've seen CF apps with client variables in a database in a
clustered non-sticky environment work well.
>
>
> I would lean towards the J2EE duplicating sessions as a solution
personally. You can read more about it at www.bpurcell.org.
>
> - Calvin
>
> -----Original Message-----
> From: Al Everett
> Date: 9/29/04 9:51 am
> To: CF-Talk
> Subj: SESSION vs. CLIENT
>
> We're working in a clustered environment (eight servers in one pool, two
> in several others) on Windows 2000/IIS 5.0 behind a BigIP load balancer
> with some CF5 and some CFMX. (Very soon to go all CFMX.)
>
> We use Session variables extensively to keep track of user's logon
> information, which has required us to use "stick sessions" on the load
> balancer to keep users stuck to a server. However, we've gone through
> several exercises with certain customers because of the way their proxy
> servers/firewall block or trap cookies or other issues.
>
> I have suggested that if we were to go to Client variables in a database
> for that information we would remove the need for sticky sessions. The
> argument against me has always been that a database transaction is too
> expensive. Back before our database was tuned and we resolved a bunch of
> network issues I would have agreed, but we're almost guaranteed to have
> at least one call to the database on every page load right now and the
> site is fine. (Oracle 9i running on Solaris.)
>
> Does anybody have any good statistical and/or anecdotal evidence on
> whether Sesssion is better or worse than Client variables, specifically
> in CFMX6.1?
>
>
>
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>
>
>
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