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I have a question regarding payment at the Cloud Firestore compared to the Realtime Database. At Firestore you pay per read/write per document, right? In other words: If I display a list of 1000 documents in a collection, do I pay for 1000 reads?

I have a few collections in my app with many (200-300) documents, which unfortunately all have to be displayed on one page. My app has about 10,000 active users. After the calculation I am definitely financially broke... :-)

Therefore my question: Are 300 elements also 300 reads taken into account if I save the 300 elements in ONE document as an Array and retrieve them? Is then only the one document calculated as a read? Or also the 300 elements from the created array?

Frank van Puffelen
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Vueer
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1 Answers1

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If I display a list of 1000 documents in a collection, do I pay for 1000 reads?

You only pay for documents that are read on/from the server. Most Firestore SDKs implement a client-side cache, which may significantly reduce the number of documents that are read on/from the server.

I have a few collections in my app with many (200-300) documents, which unfortunately all have to be displayed on one page

One way to reduce the number of read operations is to model the data for that one page into a separate single document. This document is essentially the data for a single page in your app, meaning that you update it whenever any of the underlying data updates. That leads to more code when you write updates to the database, but it saves you 299 document reads for every user accessing the page.

Also see:

Frank van Puffelen
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  • Thanks for your answer! :) Do you mean the basic offline persistence from Firestore with "client side cache"? Does I not pay do reads from offline cache? And: If I read 1 document with an Array as value with for example 500 entrys...does I pay for 1 read? – Vueer Feb 24 '19 at 23:25
  • Only document reads from (and on) the server are charged. Document reads from the local cache of the device are not. Fields in the documents are never charged separately. – Frank van Puffelen Feb 25 '19 at 00:25