If you want to know what tables you are reading in a given program, you can use _UserTableStat. This assumes that (a) you have that VST, (b) you configured the -tablerangesize and -basetable startup parameters appropriately before the most recent database start, and (c) you have access to an editor and can write a bit of 4GL code.
This VST contains counters for each table for record creates, reads, updates, and deletes. Read the stats before you run the program and again afterwards and you will see which ones you are accessing based on which counters have changed.