I have an application that displays some data retrieved from the database on index.cfm. It retrieves a few fields/columns from a table and displays them on screen. Users make modifications and save it - using a button. The page calls a cfm that calls a database (sql server) procedure to save it. I am trying to understand what will happen when multiple users access this. Multiple users are accessing this. I am not explicitly using any cfthread or lock to protect anything. I access a few session variables to identify the user who is logged on - and present some information relevant to them. How does Coldfusion keep the invocation of that index.cfm by multiple users separate and provide state?
CFTHREAD probably won't make any difference, for you (unless you have over 100,000 users at a time.) However, you should most definitely be using an exclusive CFLOCK around the query that SELECTs the information, as well as the query that UPDATEs the information so that user A isn't reading the data at the same millisecond user B is updating it.
ColdFusion uses a combination of CFID and CFTOKEN to keep sessions identified with particular users.
I hope you are at least using CFQUERYPARAM when updating information to the database.