Only retrieve changed document field

Question

I found out that listening to document changes will always download the full document over and over.

I have a problem with this in the following scenario: The

Answer 1

Firestore always returns complete documents. There is no way to get it to return a subset of the fields in a document, neither by explicitly asking for those fields (akin to a SELECT FIELD1, FIELD2 statement), nor implicitly asking (as you do by wanting only modified fields).

If you want to limit bandwidth usage for frequently changing documents with a large payload, your workaround of putting the more static part of the data in a separate document is valid.

Also see:

• How to access a specific field from Cloud FireStore Firebase in Swift
• Firestore - get specific fields from document
• How to allow only particular fields of a firestore document to be accessed publicly