If you attempt to update a record, you send a uuid to server B representing the document you're attempting to update; if sever B doesn't have that document yet (either because it hasn't been created on server B or because it is not yet updated to the latest changes on server B), that change will be rejected.
If you are just expecting the document to be a member of a list (say, you put an order on server A, then look for all orders belonging to a customer on server B), you're not guaranteed to see it. This is 'eventual consistency' -- in practice, you want to be sure that you can live with this as a tradeoff.
If you are just expecting the document to be a member of a list (say, you put an order on server A, then look for all orders belonging to a customer on server B), you're not guaranteed to see it. This is 'eventual consistency' -- in practice, you want to be sure that you can live with this as a tradeoff.