What's the proper way to add/update data in Firestore when offline?

Question

When my app is offline and I am adding or updating a document the memory increases. Also, showing lists of documents take longer to load. If I run the same code when the dev

Answer 1

Cloud Firestore uses SQLite for its persistence mechanism. So for intermittent periods of offline activity, you shouldn't have problems with performance or durability.

However, if you intend to use a Firestore database for very long periods of time, there are some things you should be aware of. Cloud Firestore was not built as an offline database, is an online database that continues to work when you're offline for short or longer periods of time. When offline, pending writes that have not yet been synced to the server are held in a queue. If you do too many write operations without going online to sync them, that queue will grow fast and it will not slow down only the write operations it will also slow down your read operations.

So I suggest use this database for its online capabilities. As one of the Firebase engineers said and I quote, "It is impossible to build a slow query in Firestore". So, the performance comes from the new indexing capabilities on the backend and these optimizations don't exist when you're offline.

One more thing, if you have many offline clients who are trying to write to the same document, only the last one will be actually be written to servers when the state is changed.

So, to answer your question, there is no proper way to add/update data in Firestore when offline, to have a less memory usage. Just go online and that's it!