Firestore: How are “reads” calculated for the quota?

Question

I don\'t understand the way \"firestore\" counts the reads for the quota and billing.

Example: I have a collection with 200\'000 documents. Every document has a timestam

Answer 1

To allow that query, you will need to have an index on timestamp. Firestore uses that index to determine what documents to return. So this would count as 10 document reads.