Just being a curious George here.

But I'm handling 279 million data points (x,y) and am wondering if pyplot can scatter such a number?

Thanks.

If you want to colorize each point on a usual HD screen that would result in ~2 million points. It does not seem to make sense to plot more than 100 times that much data. Apart this is surely a question of available memory and computing time.

So I ran the experiment. After 15 minutes the plotting window appeared on screen, being completely black. After another 15 minutes the plot was drawn on screen. Makes 30 minutes in total. This was done using python 64bit on a 3GHz computer with 16 GB RAM.

Note that I did not colorize the points differently, which would of course still increase draw time.

So the answer is: Yes, it's possible. ...but probably not useful and there are much more efficient ways to draw points on a screen.