Hello,
I have an application that inserts multiple rows within a single
partition (= all rows share the same partition key) using a BATCH
statement. Is it possible that other clients can partially read that
batch or is the batch application isolated i.e. other clients can only
read all rows of that batch or none of them?
I understand that a BATCH update to multiple partitions is not isolated
but I'm not sure if this is also the case for a single partition:
- The article Atomic batches in Cassandra 1.2
<http://www.datastax.com/dev/blog/atomic-batches-in-cassandra-1-2> says
that /"... we mean atomic in the database sense that if any part of the
batch succeeds, all of it will. No other guarantees are implied; in
particular, there is no isolation"/.
- On the other hand, the CQL BATCH
<https://cassandra.apache.org/doc/cql3/CQL.html#batchStmt> docs at
cassandra.apache.org mention that /"/ /... the [batch] operations are
still only isolated within a single partition"/ which is a clear
statement but doesn't it contradict the previous and the next one?
- The CQL BATCH
<http://docs.datastax.com/en/cql/3.1/cql/cql_reference/batch_r.html>
docs at docs.datastax.com mention that /"... there is no batch
isolation. Clients are able to read the first updated rows from the
batch, while other rows are still being updated on the server. However,
transactional row updates within a partition key are isolated: clients
cannot read a partial update"/. Also, what does /"transactional row
updates"/ mean in this context? A lightweight transaction? Something else?
Thanks for any help,
Martin
