Improve performance of android-app with large data

[StefanKock]

Situation Description & Motivation

The data sync from the backend to the android-app is quite slow.

Related: #7734

Use cases

This is a rough summary of what is currently being synchronized (for Surveillance Officer):

Cases

• reporting user
• responsible user
• district
• Contact.sourceCase (reporting, responsible, district)
• country shared

Contacts

• reporting user
• responsible user
• district
• Case.contacts

Samples

• cases, contacts, event participants

Events

• reporting user
• responsible user
• district
• event participants by resulting cases
• event participants by district

Event Participants

• event

Personen

• district (address)
• case, contact, event participant, immunization

High-Level Explanation

This is how we could prioritze data to send only a part of it for certain diseases/users:

Prio 1

• reporting user
• responsible user
• +event participant: reporting user -> + related event (maybe pseudonymized)

Prio 2

• Cases: Source cases of (Prio 1) contacts (+ in district)
• Contacts: Contacts of (Prio 1) cases (+ in district)
• Event: district, but withouth event participants

Prio 3

• District
• Country shared
• (Source cases + Contacts of those)
• Event participant: All by district and by event (except in other district) (maybe pseudonymized)

Prio 4 / Pseudonymized data

• Source cases outside of district
• Contacts of cases outside district
• Event participants outside district

Remove

• Event participants by resulting case (since we are not doing it for contacts)

Timeline

Tasks

Make mobile app sync more robust

• [x] #7266
• [x] #7302
• [x] #7303
• [x] #7521
• [x] #7604
• [ ] #9437

Performance

• [x] #8357
• [x] #8946
• [ ] #9320
• [ ] #10293

Reducing data synced to the mobile app

• [x] #7304 OR immediately archive "not a case" cases
• [ ] #7305 -> per disease?!
• [ ] Allow filtering of cases/etc. by their sync status (new, unsynced changes)

Additional options

• [ ] After infrastructure sync allow user to work. Sync cases, etc. in background. When user wants to push data, cancel background sync.
• [ ] Allow synchronization of an individual case or contact including related samples
• [ ] Limit synchronization to priority one data. Users should have a link to switch to the web app

Risks

Additional Information

• Some tickets of #7734 improve the performance under the hood by speeding up filter logic.