Allows say I've got a datbase of Cars. I've Models and makes (FK to Makes). I intend on getting customers track their cars. each Vehicle includes a FK to Model. Now, I've got a large amount of customers, and I wish to separate my database to distribute load. The Models and makes tables don't change a lot, but they should be shared across shards. My thought is by using MySQL replication from the master DB of models and makes to every slave database. My real question is: Can One securely email the slave databases presuming I do not email individuals tables around the master?

Even though about them, can there be anyway to ensure one slave database has got the latest data? For instance, someone just added the 'Taurus' make, after which really wants to add their vehicle. Can One be sure that the slave database they're using has got the latest master data?

Yes, generally you are able to securely email a table around the slaves that's not written around the master. Should you choose such things as place auto_increment rows around the slaves as well as on the actual, individually, you'll obviously have problems. You need to configure that table to become excluded from replication entirely, really.

For checking whether you will find the latest data, SHOW SLAVE STATUS features a area Seconds_Behind_Master that informs you if the slave is current. Clearly you would like it to be zero. To make sure that placed and duplicated information is present, obviously, you have to wait another and then observe that Seconds_Behind_Master is zero.