Slow case downloads by mobile users

Dear CommCare users!
How to minimize the slowness of case downloads by mobile users?
My project currently has more than 150,000 cases and 395 case properties.
To avoid slowness the cases are subdivided into 24 groups so that when the mobile user is assigned to a group, he only downloads the cases of his group.
I use phones with 9GB storage and 2GB RAM.
The problem is that currently downloading cases to mobile for groups with more than 6000 cases always takes a long time and this causes a lot of problems for my mobile users.
Can anyone give me an idea on how to reduce the slowness to a minimum?


It’s good that you’ve identified the Groups feature for distributing data, splitting up case loads effectively is a key element of the system.

Depending on your use case, you may also want to consider using A Locations Hierarchy to configure case sharing rather than explicit case sharing groups. Locations are a bit easier to maintain and provide additional features/options, but ultimately the behavior on device will be similar.

There are a couple of tricks for syncs of that number of cases which can improve things, but I’m a bit surprised that syncs are slowing down with 6k cases per user since the syncs are incremental and only send down changed data.

It might be that there are some configuration components which aren’t set to an ideal state. Can I ask that you Report an Issue through the CommCareHQ interface so someone from our team can check and follow up on that?