Adding a second database to replication... How?

[David Strang]

All -

I've just recently jumped onboard with doing MySQL replication. I eventually want to replicate the majority of my databases, but figured I'd start with just one. I followed the documentation here on mysql.com with one small twist... rather than use FLUSH TABLES WITH READ LOCK and mysqldump, I used mysqlhotcopy with the --record-log-pos switch. It worked great, and I was able to bring the slave database online and get the replication going without a hitch.

Here's the problem... I want to add another database. How can I do that? When I issue the CHANGE MASTER TO command with the new log file and position... what happens to my existing replication? Is it smart enough to know it doesn't need to playback all of that because some of the items may already be in sync?