Graceful is a misnomer, but there are better versions. If you are day, a database server, and you run out of memory and die horribly, availability for all clients is compromised. If you begin rejecting queries or connections until memory js available at least some availability is maintained.
I don't follow, it seems like you're still be hosed in this scenario. What's the difference of stopping accepting connections and rejecting queries vs crashing out? Meaningful work cannot make progress when a busy dynamic system is OOM -- which a database is a prime example of.
Best to avoid the condition, or design the client side to handle the possibility the resource could be unavailable.
