How many documents are queried?

[itismejy]

In the documentation:

🚨 Limitation: currently limit and orderBy queries are not supported because of the geo hash query algorithm and Cloud Firestore query limitations. Alternatively documents can be sorted on client side after getting the data (documents).

I would like to ask, how many documents are queried maximum?

[kosukesaigusa]

@itismejy

how many documents are queried maximum?

Do you want to ask how many documents are retrieved at maximum as geoflutterfire_plus queries?

The maxim number is not set by geoflutterfire_plus package, but for now you can't set orderBy to your query, so even if you set limit to your query, it might not work as you expect.

[itismejy]

Hi there, I was wondering if this is possible?

https://stackoverflow.com/questions/62175796/limit-the-retrieve-of-documents-from-firebase-on-flutter
Query query = cities.orderBy("name").limit(3); // descending order

Query query = cities.whereGreaterThan("population", 2500000L).orderBy("population").limit(2); // ascending order

In your code for geoflutterfire_plus, i see this:
@VisibleForTesting
Query geoQuery({
required final String field,
final String geohashField = 'geohash',
required final String geohash,
final Query? Function(Query query)? queryBuilder,
}) {
Query query = _collectionReference;
if (queryBuilder != null) {
query = queryBuilder(query)!;
}
return query
.orderBy('$field.$geohashField').limit(5) // add the limit here, and alllow user to pass it as a parameter
.startAt([geohash]).endAt(['$geohash$_rangeQueryEndAtCharacter']);
}

I see you are doing the query with cloud firestore https://firebase.google.com/docs/firestore/query-data/order-limit-data#dart
in their docs they do this:
final citiesRef = db.collection("cities");
citiesRef.orderBy("name").limit(3);

Could the query be changed to:
query.where('$field.$geohashField', isGreaterThan: geohash,
.orderBy('$field.$geohashField').limit(5); // add the limit here, and alllow user to pass it as a parameter

[kosukesaigusa]

@itismejy

It is possible to add .limit(N) to your query, and it certainly returns N or less documents.

However, you can't set orderBy to your query, so the result might not work as you expect in terms of its order (it is not possible to get to know which N documents are retrieved from the query).

[bw-flagship]

Maybe we could change the docs of this page. It says

🚨 Limitation: currently limit and orderBy queries are not supported because of the geo hash query algorithm and Cloud Firestore query limitations. Alternatively documents can be sorted on client side after getting the data (documents).

After reading this thread it makes sense, but on my first read I thought that limit-queries (without orderBy) aren't supported either.

[kosukesaigusa]

@bw-flagship

Thank you! I'll think about updating README to avoid confusion!