Parameterize a Load Test while running a web test?

I currently using a WebTest to test a system. The user can vote and then can't log back in to change his vote.

The WebTest use a list of username from a CS开发者_C百科V file and all the account have a default password for testing purposes.

Since I wan't to see how the website will react with a lot of concurrent user login in at the same time, I wonder how to parametrize the Load Test.

Ideas? Solutions?

I tested a solution that would have up to a couple hundred thousand users logging in over a four hour period.

We converted our load test to a coded webtest in order to call a specific database procedure that would give us the next login from the list.

We stored an index into the table in this procedure and moved it up one each time a new login was given out.

This stored procedure was very simple, but uses the database concurrency protection to make sure the users were given out exactly as stored in our temp table.

Ideally you do not want to put a thread blocking call (database or file IO) in your load test code as many virtual users share the same thread. In practice however, this worked fine for the simple stored procedure we were calling.