> - return from a write call silently, when the data wasn't written and will not be
There isn't some defined set of rules for how a database should operate. This attitude implies that an asynchronous database should never ever exist. If that's the case, how could I ever use a database for HTTP logging? I can't have every single HTTP request block on a database write, that's absurd. HTTP logging is impossible with MySQL or PostgreSQL for exactly this reason.
The reason for the deprecation seems to be the many gotchas with it combined with the doubtful performance gains. It seems to have been an ugly hack.
Is a process that send data from socket > /dev/null a database as well then. Why not call that a database too?
> If that's the case, how could I ever use a database for HTTP logging?
In a normal database, you would possibly switch 'durable writes' and possibly 'time expiration' feature in the configuration file from the default OFF to ON.