Queries scale with the size of your result set, not the size of your data set

Issue

This is a question about the latest Firebase Cloud Firestore.In this doc it says like this:

It also allows for expressive queries. Queries scale with the size of your result set, not the size of your data set, so you'll get the same performance fetching 1 result from a set of 100, or 100,000,000.

This statement is not clear for me. Can you explain little bit more about this use case?

Solution

This may be written a bit confusing. It is not a use-case in the classic sense its just a statement about the performance of Firestore.

It basically says that it does not matter if you request 1 item out of a 100 or 1 item out of 100.000.000, it will be equally fast. Here 1 is your result set and 100/100.000.000 is your data set. So requesting 1 item out of 100.000.000 will be faster than requesting 50 items out of 100.

I hope this makes it a bit clearer!

Answered By - David