Firestore 不返回集合的所有文档

Question

I am writing a flight planner for android. For the use of a certain REST API I need ICAO identifiers for each airport. I am trying to fetch about 14k documnets from firestore and map them to objects. Structure of my firestore:

In the result I got exacly 7698 documents in return every time.

    val db = Firebase.firestore
    val airports = db.collection("airport")
    val myColl : ArrayList<AirportDAO> = arrayListOf()
    val start = System.currentTimeMillis()
    var end : Long

    airports.get().addOnSuccessListener {
        end = System.currentTimeMillis()
        Log.d("firebase", (end - start).toString())
        val docs = it.documents
        Log.d("size", it.size().toString())     // <-- 7698
        for (doc in docs) {
            val a = doc.toObject(AirportDAO::class.java)
            if (a != null)
                myColl.add(a)
        }

        Log.d("size", myColl.size.toString())  // <-- 7698

    }

Method get() should return all DocumentSnapshots. Are there any limitations I am not aware of?

@Edit: End of my collection. "Filtruj" means "Sort" in Polish

Answer 1

Adding a listener on the following reference:

val airports = db.collection("airport")

It means that want to get all AirportDAO objects that exist within your airport collection. If the size of your myColl list is 7698 , it means that you'll be charged with 7698 read operation when you access that collection, which in my opinion is pretty much.

I have exactly 14110 documents in my collection.

No, you don't, You have exactly 7698. that's what your code says.

If you want to filter the results, you should use Query . If you'll always need all of them, then you'll create a heavy traffic with Firestore.