I'm using Firebase's Cloud Firestore in an Android application for receiving product information. The Android client only reads from Firestore and never writes. Offline persistency is enabled. The product information is updated once a week.
I've received several reports of customers that claim that they still see outdated data even after I've changed the data in the cloud. These reports come in even days after the import so I guess their smartphone had an Internet connection in the meantime and it's not a connectivity issue.
The point is I could never reproduce this. I've checked the code a few times but don't see any error on my side. I'm reading from Firestore once when the view is rendered. I do not use snapshot listeners.
I know this is all very vague so I'm just asking if anyone else made the same experience with Firestore on Android with offline persistency enabled?
Version of the Firestore library is 17.1.5.
I haven't had the same problem, however, just to help (maybe it's useful), few things to mention here, about how Cloud Firestore works:
First time the client-side SDK fetches, it fetches from the server, saves the results to the cache.
The second time you fetch, the first results will always come from the cache, until you fetch them from the server.
Until you fetch the new values from the server, they will keep coming from the cache.
You have specifications such as Source.SERVER or Source.Cache. If you can't really reproduce this, I might really think that this is something to do with the connection of your customers. However, for you to actually debug this and see the percentage of this happening, I would suggest you to (to actually see the impact and be more data-driven):
Add a timestamp object to your Firestore, whenever you update your information (as per week you say)
Add the same timestamp to Firebase Remote Config for a key
Fetch these in your clients and compare, if not the same, and if the one from Remote Config is never, that means you hit the user group that has the described problem.
Just a dummy test for you to actually see the impact. From my current PoV, I can't help you more than this. However, I would also urge you to bump up your versioning on Cloud Firestore, currently, it's 21.3.0.
Related
We store device status in Firestore from an Android tablet. This could be if a printer is online or offline.
When the tablet goes offline for a while and comes back, we see a lot of write churn where each write for i.e a printer will be 'played back'. We are really only interested in seeing the last write for a given doc id. Is there a way to tell firebase that newer writes should completely replace older ones before hitting the server, once online?
Is there a way to tell Firebase that newer writes should completely replace older ones before hitting the server, once online?
Yes, there is. You should consider writing the data in the exact same location. When it comes to Cloud Firestore, you should always write the data in the same document. It doesn't really matter how many updates you do while offline, when the device regains connectivity, you'll only get the last update.
I am building an app for a gym which shows gym members info in a recyclerview at the app startup , the problem is at every fresh launch of the app the data is pulled from the firebase database and appears suddenly after 4-5 seconds in the recyclerview after the app starts, and i think this time will increase as the data grows.
If the data is same why pull it every time.
But i want to go one step further
what i want is when the user logs in for the first time all the data liked to that account should get pulled off and stored locally , i don't want to pull the data ever again even if the user is connected to internet, the changes user make should be made to realtime database as well as locally regardless how much data is created , so that i never need to pull data again once the user is logged in but just push the data every time it changes or grows or gets deleted, operations will happen to both local storage as well as at realtime database, so the user will always have local access to data he created.
And if he logs in again same thing happen again.
Is there a way to do it with firebase without implementing local sqlite database together with firebase realtime database.
This answer is for a use case where data is stored locally as well as on a remote server - similar to what's in the question. It may not specifically answer the question but may lead to a solution.
In the question, it appears there's local data and remotely stored data which are essentially the same - the OP is using sql to store locally and Firebase to store remotely. This is being done to 'speed up' the loading process and lower the amount of reads.
My suggestion is to use Firebase only. It's very fast and if coded correctly, the loading time should never be 4-5 seconds before the UI is available to the user (barring a bad internet connection if not using persistence).
Additionally, Firebase offers locally persisted data in two ways; cached data and persisted data (which are similar but read on)
Cached: Firebase apps automatically handle temporary network interruptions.
Cached data is available while offline and Firebase resends any writes
when network connectivity is restored.
and
Persisted: By enabling persistence, any data that the Firebase Realtime Database
client would sync while online persists to disk and is available
offline, even when the user or operating system restarts the app. This
means your app works as it would online by using the local data stored
in the cache. Listener callbacks will continue to fire for local
updates.
There's a lot more to it so please see iOS Offline Persistence and Enabling Offline Capabilities on Android
Your questions suggests that the Firebase SDKs provides this sort of functionality. It does not. You will have to implement something yourself.
The best way to tackle this in an easy and the most efficient way is to use the Room Persistence provided by AndroidX Architecture.
It is technically an ORM over SQLite. Please find the details here:
AndroidX Room Persistence
I'll like to know if it is possible to increase the size of the local cache of the firebase firestore database?
Will also like to deepen my knowledge on how firebase firestore offline
data persistence functions on mobile( android specifically).
Let me explain my use case and you evaluate if firebase firestore is the route to go for me.
I require a local database that can be synced averagely after every 24 hours and I require it to function offline and persists it's data. The main use case is this: I have a messaging feature integrated into the application and just as everyone expects to see his messages he's got to send and receive before he was disconnected that is, just as even when one is disconnected, he still can see his different conversations on whatsapp even after a phone reboot, that's how i expect my application to follow and I want to know if firebase firestore local cache offers me this possibility of persisting the cache even after phone reboot without having to connect to the internet? I do expect a lot of reads from the local cache but not that of writes while offline.
To summarize my question, can the local cache persists changes that have been made while the phone was offline even after phone reboots without any connection to the internet? Thank you all for your answers and time taken to read this in advance.
Please, do include some helpful links to tutorials showing how to use it if you do know any of them.
The size of the local cache depends on the size of the storage of your device. If you want to increase the size of your local storage, then you just need to free some space or buy a new hardware. There is no limitation regarding the maximum size that can be stored on your device.
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. So, Cloud Firestore persists the data you write on a device to a local database. So the next time you start the application, it will indeed be able to read that same data, even when the device has never been connected to the Firebase servers. And as an answer to your question, yes it can.
But don't use Cloud 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 a queue of all your write operations. As this queue grows, local operations and app startup will slow down.
Nothing major, but over time these may add up. But remember, all these operation will persist even if you restart the device. You not gonna lose any data.
I am currently using Firebase Firestore as a primary backend that retrieves data from a variety of sources. I also use Android's Room for my mobile backend. When the phone receives data it is stored in the Room database in the event the user will not go online again for days even weeks.
After looking through the device files, I see firestore saves the data in files under the /data/data/<your-app>/databases directory.
The file looks something like this
I have read the offline persistence docs on the firestore and there is no indication on how durable the offline persistence is It mentions that the data is cached but not for how long. My question is, what is the durability of Firestore's offline persistence. Would one recommend using it instead of having a fully-fledged local DB to store data that may not be synced over long periods of time (days,weeks)?
It seems to already handle syncing data well once a connection is re-established. Im just worried that after some point that file may be deleted by the system and the user loses everything.
On Android (as of this writing) Firestore uses SQLite as a persistence mechanism. So for intermittent periods of offline activity you should have no problems with performance or durability.
However if you are going to be offline for days or weeks (as you said) there are some things you should be aware of:
Performance
Because Cloud Firestore is meant to be used mostly online, pending writes that have not yet been synced to the server are held in a queue. If you do many pending writes without going online to resolve them, that queue will grow and it will slow down your overall read/write performance. Most of Cloud Firestore's performance guarantees come from indexing and replication on the backend, but most of those optimizations don't exist when you're operating offline-only.
Conflicts
Firestore's basic conflict resolution model is "last write wins". So if you have many offline clients writing to the same document, only the last one to come online will actually "win" and persist their change.
Features
Most of Firestore's features work offline with one major exception: transactions. Transactions can only execute when you are online. So if your app uses transactions it will not work properly offline without some special handling.
There is no indication in offical documentation on how durable the offline persistence is because it cannot be predicted. This question cannot have an exact answer, like 4 weeks or something like this because it depends on how many write operations take place while you are offline.
I recommend you not to use Cloud Firestore as an offline-only database. It's really designed as an online realtime database that can work for short to intermediate periods of being disconnected.
While offline, it will keep queue of all your write operations. As this queue grows, local operations and app startup will slow down. But you need to know that these operation will persist even if you restart the device. You not gonna lose any data.
The Goal: I'm working on a simple project with Android Studio and Google App Engine. The App is just a Proof of Concept, so nothing spectacular. In a sentence, it is an app that counts the number of times a button was clicked in a six hour interval. Specifically, when a button is hit, the app needs to send a request to the backend. The backend then needs to load a number from cloud storage, increment it, and write it back. Every six hours, I need to reset the counter to zero.
The Current Progress: I have the app UI written, I have an App Engine Project set up, and I have the two connected via endpoints. For now, I have a method to send two numbers to be added in the backend and return it. I'll scrap that and go with the incrementor code when the time comes, but I can say I understand how App Engine and Android are connected.
The Problem: How do I access Google Cloud Storage programatically from here? Do I write backend code? Do I write code in the App itself? Do I do some more endpoints wizardry?
I keep seeing code excerpts, however, I don't know how everything fits together. I can access cloud storage from the online manager, however, that doesn't do much good I don't think. I understand how buckets and entities are broken down as well, if that helps.
Thanks in advance, I've been wandering through the desert of Documentation for weeks.
It's a little unclear exactly what you're trying to accomplish, but I'll take a crack at hopefully nudging you a bit more in the right direction.
First off, if you're just needing to load and increment a number, in my opinion, you may be far better served using a database, such as Google's Cloud Datastore, rather than Cloud Storage.
There are numerous options for connecting, whether you end up on Cloud Datastore or Cloud Storage. You may find it easiest to implement your Storage/Datastore operations on App Engine, but that really depends on what else you're doing.
If you app just needs to do basic database or storage operations, I wonder if you might not be far better served by a more managed solution like Firebase. With Firebase, you get many of Google's cloud services, nicely wrapped in an API that is very easy to implement, thereby negating the need to manage a separate App Engine instance and your endpoints. Firebase also gives you offline and caching functionality.