My prior startup tried to do a security product with backend in Mongo. It really needed transactions and to avoid N+1 issues.
DB team insisted on writing "DAOs" that ended up pulling 1GB+ of data back from Mongo to merge in EACH of 100+ data points from a scanned machine. Similar issues in UI presentation. With multiple threads doing each of these things simultaneously there were many out of memory dumps. I analyzed these multiple times and told the DK VP Engineering what the problems were, and they didn't follow up for 6 months. He was gone soon after.
DB team insisted on writing "DAOs" that ended up pulling 1GB+ of data back from Mongo to merge in EACH of 100+ data points from a scanned machine. Similar issues in UI presentation. With multiple threads doing each of these things simultaneously there were many out of memory dumps. I analyzed these multiple times and told the DK VP Engineering what the problems were, and they didn't follow up for 6 months. He was gone soon after.