since firebase doesn't delete a subcollection automatically once the document is deleted, I'm thinking of a workaround using an "admin" app.

1. I have the documents have a field called "marked_for_deletion" with a default value of false.

2. The view check for this field and if it's true, doesn't show them

3. When the user deletes the document, set this field true.

4. Then at a later time, my other app deletes all the documents recursively or iteratively.

this way, I avoid the performance hit in my original app.

What's wrong with my idea? It's probably wrong, but I don't know why.

Edit: Or I could just leave the documents marked for deletion as is and ignore them.