whisper is 12 bytes per data point. The Gorilla style time series saves gobs of data over the whisper style, there is simply little to no comparison. Gorilla is better than whisper when it comes to storing the same data in less storage space.

Disclaimer: I am a co-maintainer of graphite and try to write code for it when I have free time (so not much right now or for the past year or so)

https://github.com/graphite-project/whisper/commits?author=S...

In this case Tgres beats Whisper by quite a bit - it uses 8 bytes per data point. In fact looking at the numbers for a small test db I have 2,057,275 points taking up 16,687,104 bytes, which is exactly 8.11 bytes per point.

BTW getting the total point count is as easy as:

  select sum(array_length(dp,1)) from ts;

If you adjust the width (i.e. points per table row) to a higher number than the 768 default, as soon as you get above the PG pages size, TOAST (https://www.postgresql.org/docs/current/static/storage-toast...) kicks in, which PG compresses. Not sure how well this works, but at least in theory it should make it even more compact (though not sure about it being as performant).

My guess is that whisper would be more efficient on disk, not by much though. But whisper won't let you

  SELECT ... 
    FROM tv
    JOIN customers ON ...
    JOIN purchases ON ...