I'm trying to switch from SQLite to Cloud Firestore in my app. And ofcourse, I'm trying to reduce the number of reads from Cloud Firestore.
I get a stream from Cloud Firestore like this:
list = fireStore.collection('users')
.document('public')
.collection('info').orderBy("date")
.snapshots();
All the documents from the collection 'info' is to be read. When read for the first time, I'd like to force future reads to be from the cache. Until, let's say, 20 days has passed. Then I'd like to update the cache.
This is as I understand it, possible with DocumentReference.get() and Query.get() (click here to find out how), but as far as I have found out, not possible with my solution.
Do I need to change my approach and implement one of the methods above or is there a work around for stream as I've used it?
The snapshots method in FlutterFire is the equivalent of onSnapshot in the native SDKs. These methods listen for changes on both the local cache and the server, and cannot be configured otherwise.
The get() methods in the native SDKs and FlutterFire can be configured to get the document(s) from a specific source. So if you want to force reading from the local cache, you'll have to use get(GetOptions(source: Source.cache)).
An alternative approach could be to explicitly manage network access for the Firestore client.
Related
I have more than 52k hits on my small project which is using NextJS with Firebase 9.
I don't know what the problem is because the data I am using is very limited and I have only two snapshot listener and one Authentication feature. But somehow in just two days Firestore quota has exceeded and there are more than 52k READ hits.
I don't know why that happened because there are no memory leaks and I am also closing the API listeners which come attached with Firebase.
I am providing github link in case anyone wants to take a look https://github.com/jainChetan81/Todo-List
Attached screenshot of Firebase console:
Use of the Firebase console will incur reads. If you leave the console open on a collection or document with busy write activity then the Firebase console will automatically read the changes that update the console's display. Most of the time this is the reason for unexpected high reads. You can go through this answer. Also, currently there are no tools to trace the reads in Firestore. So to limit the Firestore database reads you have to configure security rules.
So, I would suggest you check your Firestore rules. And if not, it is better to contact Firebase Support as this kind of issue needs visibility into your project and they will have access to it.
I am having the same problem as you with my React app. The solution is to use the useEffect hook and call the function that requests for firestore collection;
useEffect(()=> {
getPosts();
}, []);
I have a single page web application and I have NOT enabled offline persistence.
A component in this application has subscribed to a document using the onSnapshot function and recieves updates.
An other component in the same application instance reads the same document using the get function. Will firebase provide the same instance of the document, which is already loaded in the subscription? Or will it do a new request to the server?
A third component in the same application instance subscribes to the same document. Will this trigger new requests to the server?
What about reading and subscribing collections?
What about subscribing to a collection which is already subscribed, but the second subscription is called after narrowing results with the where function? Will Firestore reuse the already loaded complete collection and filter in my client instance? Or will it make server requests?
As a rule, Firestore does maintain a local cache, mostly for latency/response, not for cost savings. That said, if a document can be read from the cache, it will be, saving the read. I wouldn't try to "design" it in, however; memory limits and other considerations mean you don't really know what's in the cache or not, and shouldn't know.
IF this performance/cost is important to you, it's better to combine Firestore with something like Redux (which I do) to maintain local "sets" of documents to reduce round-trip calls, and Listeners to keep Redux current.
yes. Firebase stores documents and collections in cache memory. when you are offline you can access cache copy of data. also you can manage cache copy of documents and collections.
read this offical docs for more info
https://firebase.google.com/docs/firestore/manage-data/enable-offline
Going through this blog, I could see that my app would be better off using the Firebase cloud functions for Firebase Firestore rather than directly accessing Firestore using client-side SDK.
I can implement the Firestore READ operation using get(), WRITE operation using set() or update() &
DELETE using delete() methods. All these one-shot operations are fine.
Is possible to implement addSnapshotListener to fetch real-time updates? If yes, how?
While it technically is possible to use addSnapshotListener, there are not a lot of use-cases where this makes sense.
Cloud Functions are short-lived, a maximum of 9 minutes, so not well suited for scenarios where you need to listen to the database for longer times.
Typically, you'll want to instead define a separate Cloud Function that responds to the thing you'd otherwise want to listen to.
Realtime listeners are not compatible with the way Cloud Functions works. Functions can only run for a limited amount of time and are shut down after that timeout expires. Database listeners are indefinite, and will continue listening until they are removed. If you add a listener inside a function, the system will still shut it down after the function timeout expires.
It's unclear to me why you need a listener in a Cloud Functions, but it's almost certainly not the right thing to do, given the way functions work.
tldr: I need to have Google Cloud Functions on my own backend.
I write application, which uses firebase (especially firestore) as a transport layer between my own backend written on nodejs and client applications.
Sometimes, I need to catch some events from client on backend, but i want to avoid perform http queries directly to my backend (because I need to catch offline status, and other problems). It is better to made some changes in firestore documents, catch that changes on my backend and perform some business logic.
As for now, It can be solved with Cloud Functions, but this solution is not acceptable, because of delay between event and function invocation, and lack of invocation order.
Yet another solution, which is currently used in my project, is to making some changes to firestore document, and adding extra document, called "event" to other collection. On a server side, using firebase-admin sdk, I subscribe to that "events" collection and get realtime updates of it.
This work great, but looks like overcomplicated. Is there any way to subscribe from my backend to get all updates of all documents of firestore? Ideal solution is to subscribe to updates, as it done in Cloud Functions: https://firebase.google.com/docs/functions/firestore-events?authuser=0
The client and server SDKs don't have this capability. Cloud Functions is really your only way to get notified of changes in Firestore that match a wildcard pattern.
It seems odd to me that Firestore would charge me for read queries to locally cached data, but I can't find any clarification to the contrary in the Firestore Pricing document. If I force Firebase into offline mode and then perform reads on my locally cached data, am I still charged for each individual entity that I retrieve?
Second, offline users in my app write many small updates to a single entity. I want the changes to persist locally each time (in case they quit the app), but I only need eventually consistent saves to the cloud. When a user reconnects to the internet and Firestore flushes the local changes, will I be charged a single write request for the entity or one per update call that I made while offline?
Firestore could potentially fit my use case very well, but if offline reads and writes are charged at the same rate as online ones it would not be an affordable option.
As the offical documentation says,
Cloud Firestore supports offline data persistence. This feature caches a copy of the Cloud Firestore data that your app is actively using, so your app can access the data when the device is offline. You can write, read, listen to, and query the cached data. When the device comes back online, Cloud Firestore synchronizes any local changes made by your app to the data stored remotely in Cloud Firestore.
So, every client that is using a Firestore database and sets PersistenceEnabled to true, maintains it's own internal (local) version of the database. When data is inserted/updated, it is first written to this local version of the database. As a result, all writes to the database are added to a queue. This means that all the operations that where stored there will be commited on Firebase servers once you are back online. This also means that those operations will be seen as independent operations and not as a whole.
But remeber, don't use Firestore as an offline-only database. It is really designed as an online database that came work for short to intermediate periods of being disconnected. While offline it will keep queue of write operations. As this queue grows, local operations and app startup will slow down. Nothing major, but over time these may add up.
If Google Cloud Firestore priceing model does not fit your use case very well then use Firebase Realtime Database. As mentioned also in this post from the Firebase offical blog, one the reasons you still might want to use the Realtime Database is:
As we noted above, Cloud Firestore's pricing model means that applications that perform very large numbers of small reads and writes per second per client could be significantly more expensive than a similarly performing app in the Realtime Database.
So it's up to you which option you choose.
According to this If you want to work completely offline with Cloud Firestore you can disable network by :
FirebaseFirestore.getInstance().disableNetwork()
but firestore will cause client offline error for first user get request, that you must consider this error as empty response.