Consistency Level of Cassandra Lightweight transactions

Question

I read about Cassandra 2\'s lightweight transactions. Is the consistency level of such a write always at QUORUM? Would this mean that even if I have a multi data center

Answer 1

The suggested Consistency Level for lightweight transactions is SERIAL. Behind the scenes however SERIAL is even worse than QUORUM, because it's a multi-phase QUORUM. As you said the situation can get hard to handle when you have multiple DC -- Datastax estimate "effectively a degradation to one-third of normal".

There is a LOCAL_SERIAL that could be perfect for your situation where all DCs receive data from a specific DC.

Here you can find more info:

LIGHTWEIGHT TRANSACTIONS
LINEARIZABLE CONSISTENCY

HTH,Carlo