Firestore - Delete Documents without Read first

Question

Is there a way to mass delete documents in a Collection without getting charged for a 'read' first?

Let's say I have a collection with 1000 documents. I decide I want to delete every document that's older than 1 day. I could use a Query to return a QuerySnapshot that returns [300] documents (DocumentReference). I don't need to read the documents contents (DocumentSnapshot), I just need to delete them.

From what I understand from the pricing documentation, because I returned a QuerySnapshot first, it will charge me for 300 reads, then 300 deletes. It doesn't delineate between "reading" a DocumentReference vs. "reading" data in a DocumentSnapshot.

Is there any way to avoid the 300 reads? I can understand that getting back these 300 documents involves effort on Firestore's end to figure out that appropriate subset of documents. But the arbitrary charge of a read no matter if you actually try to get document data (DocumentSnapshot) or not (e.g. just a DocumentReference to delete) seems like it should be possible to avoid.

Answer 1

To delete a document you must have or create a DocumentReference to that document. This requires that you know its complete and exact path to the document.

If you want to delete documents that match a certain condition without already knowing their paths, you will first need to query for those documents to determine those paths/DocumentReferences. This involves reading them. There is now way to avoid this at the moment.