Firestore filtering multiple documents pricing

Question

assume that 1000 documents in cities and only has 5 capitals are true. This query returned 5 results. Now my question is, will I be charged for 1000 document reads or 5 document reads for this query (without using .limit())?

db.collection("cities").where("capital", "==", true)
.get()
.then(function(querySnapshot) {
    querySnapshot.forEach(function(doc) {
        console.log(doc.id, " => ", doc.data());
    });
})
.catch(function(error) {
    console.log("Error getting documents: ", error);
});

Any help will be highly appreciated. Thank you.

Answer 1

You're charged for the number of documents you read, not the total number in the collection. So if you're only reading 5 documents, you're charged for 5 document reads.