I’m wondering if accessing the data from the “change” snapshot of the onWrite cloud function count as an extra read on my billings.

Thank you!

CodePudding user response：

The data from the database that is included with the payload that triggers your Cloud Function does not count as a charged read towards your database (either Firestore or Realtime Database), since they are served from within an existing data stream.

CodePudding user response：

As per the documentation,

Cloud Firestore allows you to listen to the results of a query and get realtime updates when the query results change.

When you listen to the results of a query, you are charged for a read each time a document in the result set is added or updated. You are also charged for a read when a document is removed from the result set because the document has changed. (In contrast, when a document is deleted, you are not charged for a read.)

Also, if the listener is disconnected for more than 30 minutes (for example, if the user goes offline), you will be charged for reads as if you had issued a brand-new query.

This means that you'll be charged on the 1st read of the listener and will only charge you if there are changes or writes on the current snapshot.