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Yes, I'd agree, but a fair number of database's wire protocols have no means of saying "this request is cancelled"! As for "if the requester goes away", rememb

Yes, I'd agree, but a fair number of database's wire protocols have no means of saying "this request is cancelled"! As for "if the requester goes away", remember that the requester might be a few hops away. E.g., the HTTP connection from the mobile client drops; the web server and its connection to the DB is still alive and well. I can forcefully shut that connection, but that's somewhat of a drag (I'd rather keep it open, since it is perfectly good). Beyond closing the connection, and being able to issue some form of "cancel this query" request: HTTP/1 lacks it entirely, PostgreSQL requires opening a separate connection, Redis lacks it entirely, and I think both Mongo and MySQL lack it entirely. Even support for "time this request out" is spotty.

toast0 6y ago
> PostgreSQL requires opening a separate connection, Redis lacks it entirely, and I think both Mongo and MySQL lack it entirely. MySQL has a kill command, which does need to be done on another connection (might also need more permissions, it's been a while). It's been a while since I used a lot of MySQL, but this was definitely a pain point when things went sideways.
jd_mongodb 6y ago
MongoDB has killOp which will allow a user to kill any operation they have an operation ID for: https://docs.mongodb.com/manual/reference/method/db.killOp/ https://docs.mongodb.com/manual/reference/method/db.killOp/