ODK Central - How to delete a submission

[seewhy]

MAYBE this answers the question - assuming that the delete submission function works in the same way...

Deleting media from Central submissions - does it reduce database size

Hi @seewhy, For your specific scenario, I believe this should work, though maybe not for the reason you think. It also may take ~24 hrs for you to see the size reduction. This is what will happen under the hood when you DELETE a submission attachment via the API: the data will continue be stored in the database as a blob, but that blob will be unlinked from the submission attachment record. Then a daily cron job for purging deleted forms that have been in the trash for 30 days will do its work …

So it might not be immediate recuperation of space, but once the 'trash' is purged I think that it will be recovered...