Should the table be identically same between master db and slave db while replicating using Tungsten ( both are MySQL instances )

Question

I 'd like to get an answer to this question guiding our actions:

Do we have a fundamental rule that the slave db must be identically same with master db on both count of columns and the orders?

We are using Tungsten replicators connecting a master and slave db. But we recently have a special requirement that we considering adding one more columns only to slave db ( at the 1st position ). Thus we would get a different table structure in slave db compared to master db on the same table.

We would like to know if this is workable solution. Thanks Martin

Answer 1

Yes, It should be same. Master and Slave replication run by forwarding the queries. If any insert , update, delete (DML) queries is run on Master database server, Master forward that query to slave server. If the slave don't have same schema (table name , column name) it crash the requested query from master and ultimately it crash the replication. If you want to change table name on slave just to select data you can use views. Hope this helps.