Are periodic mutations atoms in Kassandra?

Question

Cassandra API supports batch mutations:

batch_mutate (keypace, mutation_map, constency_level) . Performs certain mutations in the key space. mutation_map is a map →; an external map displays a key to an internal map that displays a family of columns in a mutation; can be read as: map →. To be more specific, a foreign map key is a string key, a map’s internal key is a name column family. The mutation indicates either the columns to be inserted or the columns to Delete. See Mutation and Deletion above for more details.

Are all mutations performed in a batch performed atomically? So, if one of the mutations fails, do the others also fail?

Answer 1

All associated with this key are atomic (therefore, batch_mutate allows you to use multiple CFs with one key).

Answer 2

All mutations for this key are atomic, but there is no isolation when reading. In addition, there are no more guarantees.

Answer 3

Cassandra 1.2-beta1 added support for atomic batch updates , here too ...

• Atomic batches are now supported on the server side, where Cassandra will ensure that (at the cost of pre-recording the batch to another node first), all mutations in the batch will be applied even if the coordinator fails in the middle of the batch.