What in an expo app could be causing occasional large data usage?

what

We are running expo SDK 33.

We are finding that some tablets we put our Expo app on have huge data usages. We are talking a gig a day. They are on all the time, but as we’ve measured our app’s normal network transmissions - it’s only around 80-100 mbs.

Androids data usage monitoring says the usage is from our app, not another one. We’ve turned off OTA updates in the manifest (app.json).

why

It’s just not scalable to have talbets that, with minimal usage, use a ton of data.

what I’ve done so far

I’m watching wireshark on the tablet, and I see some things that may be either expo or another software running on the machine. I’m seeing:

Question

It’s not on all tablets, and there seems to be no common threads between apps - so is there any way OTA’s are actually being downloaded - or partially downloaded? Or is there anything else within expo that may download, or upload anything? We’re looking for something that one in every few long running app instance may take a ton of over the wire (data/wifi) usage.

Let me know if there is any other info you need.

Cheers!

I’ve found what I believe is the culpurate. Every open of the pap graph.facebook.com is getting called (but not by our code). Must be happening somewhere within expo - usually it just makes a small call, but sometimes it goes unbounded - and just starts downloading something can’t see what with our proxy, but in a few minutes it’s megabytes (and shows no signs of slowing).

What could be calling that?

hey there, we identified this issue and fixed it in sdk36 - now the facebook sdk needs to explicitly initialized: https://docs.expo.io/versions/v36.0.0/sdk/facebook/#api

i’d recommend updating to that sdk version. sorry for the hassle

edit: you can see more information about this on the sdk 36 release notes under the " Facebook module initialization" heading

2 Likes

Thanks notbrent! Easy fix, we’ve already done that on another branch - we’ll push it our shortly.

Cheers, and thanks for the fast response.

Best,
Jono

Interesting note, occasionally when facebook initiated a connection - it would just keep downloading on a web socket connection. No idea what it’s downloading, but since our tablets are always on we’d hit 1-2gb per day of data usage from that facebook connection.
Only 90MB when it’s not hitting that facebook ‘bug’.