How hector/cassandra handles sequential operations?

Question

Using a hector Mutator I update some row over N sequential operation. Is there a guaranty, that changes happens in the order they where added to Mutator?

The simplest example, if I delete some row and then immediately recreate it. Could it not happen, that the deletion happens after inserting?

How cassandra cluster manages it, if two sequential requests are sent to different nodes? It is always possible there is few milliseconds difference between nodes...

Answer 1

Cassandra resolves conflicts using timestamps supplied by the client. In your example the 'recreate' of the row will have a higher timestamp than the row delete so it doesn't matter if somehow they got to the server in the wrong order.

One consequence of client supplied timestamps is that you either need to sync the clocks on your client machines or design your data model so that different clients don't conflict with each other.