我是否需要FCM高优先级消息才能以打ze模式将更改推送到Firestore侦听器？

Question

I'm using Firestore event listeners https://developers.google.com/android/reference/com/google/firebase/firestore/DocumentReference.html#addSnapshotListener(com.google.firebase.firestore.EventListener%3Ccom.google.firebase.firestore.DocumentSnapshot%3E) to show notifications in NotificationManager. But in Doze mode the notifications are delayed for about 10-15 minutes. Is my understanding correct that Firestore uses something like FCM normal priority messages for data synchronizations, causing the listeners to stall?

Per my requirements I need to show the notifications as soon as possible (the app is some kind of POS) and 10 minutes is too long.

I'd like to ask if following approach is feasible: I plan to use Firebase Cloud Functions triggered on changes in Firestore (Google example is for Datastore, is it true for Firestore too?) and send FCM high priority message to client, and then it will show notification. Is my assumption correct that Firestore listeners on client will be updated then, since the device woke up on the high priority message?

I plan to defer the FCM messages for about 30 seconds, to process the changes in batch. The listeners will send to Firestore DB the last time when they were activated, and the Firestore Cloud Function will check if the client's listeners were not called for some time (30 secs) and changes exist, then the FCM high priority message will be sent.

I'm worried if I'm not "inventing a wheel", as the use case seems to be quite common. Is there any better solution? For my approach I'll have to keep a table with entries per connected device, which may be large, in general. And most important that it goes against Firestore "sense" - all Google tutorials say how great it is just to register listeners and get instant updates (and it works smart I agree, at least for UI changes which obviously not important for doze mode, under the black screen) for status bar notifications (when user expects notification by sound etc) I'll have to use FCM push notifications anyway.

If go further, I can add relevant payload to the messages, to receive updates without listeners, and then what the fun is to use listeners at all? If it is correct then Firestore doesn't seem to be so sweet as it sells, at least for my case, when the Doze mode delays matter...

Please advice, may be somebody already dealed with such use case and Firestore.

Answer 1

Is my understanding correct that Firestore uses something like FCM normal priority messages for data synchronizations, causing the listeners to stall?

Firestore does not use FCM for data synchronization. It has its own wire protocol, separate from FCM.