Hi there! Could someone please explain how Column Family would be replicated and "visible / readable" in the following scenario? Having multiple geo-distributed datacenters with significant latency (up to 100ms RTT). Let's name two of them A and B and consider the following 2 cases:
1. Cassandra client X inserts row into Column Family (CF) with Primary Key = PK (all cells are set - no nulls possible). Write coordinator is in dc A. All cells in this write should have the same writetime. For simplicity let's assume that Cassandra coordinator node sets writetime. After some amount of time (< RTT) client Y reads whole row (select * ...) from the same CF with same PK talking to coordinator node from, another dc (B). Is it possible that client Y will get some cells as NULLs, I mean, is it possible to read some already replicated cells and for others get NULLs, or does Cassandra guarantee row-level isolation / atomic write for that insert? Assume that row (all cells for same PK will never be updated / deleted afterwards. 2. Same as in p.1 but after first write at PK same client (X) updates some columns for the same PK. Will be this update isolated / atomically written and eventually visible in another dc. Will client see isolated state as it was before write or after it? Thanks in advance! -- linkedin.com/profile <https://www.linkedin.com/profile/view?id=AAMAABn6oKQBDhBteiQnWsYm-S9yxT7wQkfWhSw> github.com/alexeyknyshev bitbucket.org/alexeyknyshev
