Hi Michael.
In the multiplatforms world, there are a few ways you can prevent sillyness like 14-billion-row-queries.
The simplest is simply limiting the number of queries that are returned. In the Admin client, open up the Folder, choose the permissions tab, and fill in the 'Max Hits' box with an appropriate number.
The next easiest is by inserting a default date range that you think will satisfy MOST user requests, without hitting your CPU too hard. In the Admin Client, open up the Folder, go to the 'Field Information' tab, select the date field you've chosen as your segment date (check the AG definition if you're not sure) and put in some defaults. You can use 't' for 'today' and t-90 to signify '90 days ago'.
The complicated one is writing a query restriction. In the Admin Client, open up the group that the users belong to, and under the 'Application Group Permissions' tab, choose an Application Group from the 'selected' box, and write some SQL that limits people's access based on any database field or condition that you can access in SQL. You can use the query restriction field to separate people out by offices (branch = 123) or to specific geographies (zipcode between 12345 and 54321), etc.
Hope this helps, have a great holiday!
-JD.