sometimes it's nice to know exactly how many samples are in your dataset; or if you are developing complex viz, you need to restrict your working set to a small number to manage computation time while you are designing and developing a new viz..
I find that some complex viz with table calcs and lookups can take many minutes to run if there are millions of records - I would like a simple way to tell tableau just to use the last (say) 100,000 records while I am working on my sheet. The main way to do this at the moment (in my case) is fiddle around with date ranges to try and get down to a manageable number of records for the purposes of development.
I would dearly love to be able to filter my data to say "the last million records" or something similar.
(I suppose someone is now going to tell me there's a hack to do this )