How to "Get all documents in a collection" in Firestore?

I saw the example code which "Get all documents in a collection" from the doc.

import { collection, getDocs } from "firebase/firestore";

const querySnapshot = await getDocs(collection(db, "cities"));
querySnapshot.forEach((doc) => {
  // doc.data() is never undefined for query doc snapshots
  console.log(doc.id, " => ", doc.data());
});

But I'm wondering if this really will get all the documents from the collection.

I've used DynamoDB before, in DynamoDB you can't just get all the items in a table at once, to get all the items in a table you have to paginate(send multiple requests) if the data set is too large. For example if the size of all the items is 10MB, you have to send 10 requests to get all the items.

I'm wondering if this limit also applies to Firestore? Can I really get all the data of a collection in just one request even if the size was like 1GB?

Solution 1:

I'm wondering if this really will get all the documents from the collection.

Yes it will. That's in fact precisely why that code sample is in the documentation on getting all documents in a collection.

If you think this number of documents may grow beyond what the connection or device can handle, you limit the maximum number of documents that are retrieved. If you want to then show more documents optionally, you can implement cursor-based pagination.