Firestore - Your documents should have fewer than 100 fields

Question

Your documents should have fewer than 100 fields

What exactly does it mean? If my document contains 10 fields of type Map and each of them contains 10 fields, does that count as total of 100 fields?

That's quite small... What is the reason for that limitation?

Answer 1

The document you are referring to is a best practice document. Here it is clearly mentioned that

“For the best snapshot listener performance, keep your documents small and control the read rate of your clients. The following recommendations provide guidelines for maximizing performance. Exceeding these recommendations can result in increased notification latency.”

So there is no such limit in Firestore to have a limit of 100 fields per document. It is only a best practice recommendation to improve the performance and latency.

The document states that the limit should be 100 fields per document and fields in a Map are different from fields in a document. So it does not count 10 fields of type Map and each Map having 10 fields as 100 fields.

I hope this answers your question.