Because it would mean a performance penalty for everyone who does not need MSET to be atomic without being able to opt out of that transaction. On the other han

Because it would mean a performance penalty for everyone who does not need MSET to be atomic without being able to opt out of that transaction. On the other hand, if you want to be a drop-in replacement for Redis, then this is an issue as Redis guarantees atomicity. Maybe you could have a configuration option that lets you select between compatibility and performance, at least if being a drop-in replacement is a design goal.