Explanation on limits of 50kb per interest group

[vincent-grosbois]

Hello

I've seen that this commit : https://chromium-review.googlesource.com/c/chromium/src/+/3247260 is now enforcing a limit of 50KB per interest group.

Is it possible to know what is included in this limit ? Is it only the size of the data added to joinAdInterestGroup(), or does it also include the size of the bidding functions and the size of the banners?

thanks!

[caraitto]

This is just the data added via joinAdInterestGroup(), including any user-defined signals / metadata objects, but excluding the contents of bidding functions / ads fetched separately over the network.

crrev.com/c/3253541 (which hasn't been merged yet) will further ensure that interest group updates can't result in an interest group that exceeds 50kb -- there's also a 10kb limit on the size of the update JSON sent over the network, but each update can update a separate piece of the interest group.

I think we're open to changing the 50 kb / 10 kb limits if needed, but we want some kind of limits to avoid exhausting the user's storage.