Cancel the process of exporting data if a user disconnects in Web Player

We had an unusual problem today. A user had chosen to export data from a table visualization sometime yesterday. The table they chose clearly had a huge amount of data, because we found today that the disk on one of our Node servers was filled with a 280GB file in the temporary\export folder (the file was dated as having been created yesterday morning, hence we know when the export started). We had to restart the node service (which impacted a lot of users) in order to be able to clear the file from the disk. There was no evidence of a user session being active from yesterday, so presumably the user had given up on the export and closed their browser.

Ideally the export process would recognize that the user session has closed and abort processing. It might also be helpful to configure a maximum size for export files given that no user would ever wait for a 280GB file to download!

BTW  - it's our assumption that the data in question was incorrectly large because of add column operations which add lots of duplicate rows - so another reason why we'd like better controls to help troubleshoot such issues.