Re: GRANT REPLICATION SLAVE ON db.* possible?

[Rick James]

You could use "Black hole relays". This is more complex, but probably achieves your goal.

Master -> Relay -> Slave
(repeat with pairs of Relay and Slave)

All databases are replicated to every Relay. The Relays declare all the tables (except in `mysql`) to be ENGINE=BlackHole. Each Relay has a different binlog-do-db (or set of such), depending on which Slave it is replicating to.

The relays could be on the same server with the Master, in which case they need to be configured with different Ports (and diff servers-ids). And the Slaves would connect to the different ports with different logins.

The `mysql` database would be real (not BlackHole), and would have (at least) the user+pwd for the distinct repl-user that the corresponding Slave will use. `mysql` would not be replicated to any Slave.

Each slave would have only the one repl-user it needs.