Variable length

I am not sure what the maximum values are but since they are stored in cookies or appended to the URL the size of cookie is 4KB and you can only have 20 cookies per domain (but since you can't spread values over multiple cookies) you have a 4KB restriction on each.

if you use URL to pass the two parameters then the browser and server URL size restriction will play a part in it.

CJ

Thanks, but that is not quite what I meant.

In our application, we are storing data in a table and associating it with a users session.  This data is cleared whenever the user logs back in.  In the table, I had declared the field as having a length of 4.  Well, that caused problems yesterday when the value of CFID reached 5 (rolled over from 9999 to 10000).  I posted this question and then continued to do research.  I was able to find a length for CFToken, but could not find a length for CFID.  I have since determined why.  There is no set max length for this value.  It is created as a sequential value by the CF server.  So if your server stays running without restarting or rebooting the server  for a long period of time and has high volumes of visitors, this value could reach millions or even 100 millions.

I have since adjusted the field to allow for larger values.  Thanks for your help.  I can always count on you to reply when no one else has the answer.  

Thanks, and you will probably get the points (like you NEED them).

Michael

Both of those points are good to know.

I knew CFID could get up there.. I have seen really high values.. but what the actual limit (rollover point) was, I didn't know.

CJ

I am accepting Cyrils answer as "closest" to correct.  He validated what my research had discovered.

Cheeky, if you feel you need some points or feel slighted, let me know and I will give you some points too.... ;-)

Thanks for both your help.  
Michael

Thats ok.. Just glad you were able to find what you were looking for.

 really don't need any more points :-)