I once owned an EAV DB for storing small config values. Someone wrote a great wrapper around it that made it seem like a proper DB with many tables. Since it wa

I once owned an EAV DB for storing small config values. Someone wrote a great wrapper around it that made it seem like a proper DB with many tables. Since it was for storing configs this library cached the whole thing in memory on startup. Zoom to 5 years later, we have 10+ settings for every customer in this store, and one day all our hosts keep failing over. As it turns out that small table for configs was north of 5 gigs and destroying our heap.