I suppose that you're trying to draw
all your polygons on a map at once.
Thus you're asking your Tableau Desktop
to render about 40M Marks, which is an overkill.
The reasonably high # of Marks to draw is about 1M.
Anything above that requires careful considerations
from the performance point of view.
You may want to filter out most of the Marks
(rows in your polygon datasource)
by using a filter like this:
[Point ID] = INT( [Point ID] / 1000 ) * 1000
Setting the above calc Filter to True
leaves every 1000th Mark on a view,
so your polygons would be rendered
using only about 40K Marks
(or more, but not much).
Alternatively, you would like to test a Spatial Files Connector --
a new feature in Tableau 10.2 (currently in Beta):
Thank you so much Yuri