I don't know exactly what you are looking for. If you just want a logic for incrementing the userid, try this

declare @userid varchar(100),  @delimpos int, @delimiter char(1)

set @userid ='A1'

set @delimiter =...

I think it may be a good idea to check what kind of queries are running on the server. I believe some of these queries may need lot of tempdb...

I think it may be a good idea to check what kind of queries are running on the server. I believe some of these queries may need lot of tempdb...