Yeah, it worked well during dev with my tests files too. I had like 5 events, with 2 iterations and something like 10 pictures max. I don’t really know from when the queries become so slow, I guess it’s more or less exponential.
So, there are currently 27 events. Each events has at least 2 iteration, up to 6 for now. And each iteration has between 15 to 20 main_pictures, and 20 to 100 additional_pictures.
To give you a bit of context, this is a site for a photographer that covers events every year. So there is an event which contains one iteration per year.