>Why not just query adjacent databases, rather than copying the data around? The reasons I didn't choose this way were: 1) I didn't think there's a way to write a query that can act on the data in two Databases as though it was all in one, and I didn't want to get into merging multiple database query results on the Application side. I'd rather just have all the needed data sitting in a single database so that I can perform whatever query I like without complication. 2) Most database accesses are reads, and I didn't want a big network overhead for these, especially since I'm aiming for each database to be entirely RAM resident. >If you really wanted to do this, do you need 2pc? Once data has been uploaded to the database for region A, then asynchronously copy the data to B, C, D and E later, using a queue. I've always assumed that my data needed to be consistent. I guess there are some circumstances where it isn't really a problem, but each would need to be carefully evaluated. The easy answer is to say 'yes, it must be consistent'. >If you try to commit to all at once, then if one fails, then none has the data. Yes, I'd prefer things to be that way in any event. Regards, Andy
