I created a large dataset internally (~18M rows). I wanted to change sampling to random, 10000 rows. Resampling was taking a long time and I click the "Abort" button.
When I tried to open the database again I got the "Waiting for other sample computation" message (see attached). It looks like the "Abort" button didn't work. Or perhaps it did work but it doesn't do what I would expect it to do, namely stop the resampling.
Sometimes this has happened to me. One option is go to the 'Activity' Menu (in the top left, see screenshot) and check for running process: if you see the sampling process of your dataset try to abort it from there.