The summary of your question is: is batch_mutate atomic in the general sense, meaning when used with multiple keys, multiple column families etc, correct?
On Wed, May 26, 2010 at 12:45 PM, Todd Nine <t...@spidertracks.co.nz> wrote: > Hey guys, > I originally asked this on the Hector group, but no one was sure of the > answer. Can I get some feedback on this. I'd prefer to avoid having to use > something like Cages if I can for most of our use cases. Long term I can > see we'll need to use something like Cages, especially when it comes to > complex operations such as billing. However for a majority of our uses, I > think it's a bit overkill. I've used transactions heavily in the workplace > on SQL based app developments. To be honest, a majority of application's > I've built utilize optimistic locking, and only the atomic, consistent, and > durable functionality of transactional ACID properties. > > To encapsulate all 3, I essentially need all writes to cassandra for a > given business invocation to occur in a single write. With Spring, I would > implement my own transaction manager which simply adds all mutates and > delete ops to a batch mutate. When my transaction commits, I would execute > the mutation on the given keyspace. Now this would only work if the > following semantics apply. I've tried searching for details in Cassandra's > batch mutate, but I'm not finding what I need. Here are 2 use cases as an > example. > > Case 1: Successful update : User adds new contact > > Transaction Start. > Biz op 1. Row is created in "contacts" and all data is added via batch > mutation > Biz op 2. Row is created for an SMS message is created for queueing > through the SMS gateway > return op 2 > return op 1 > Transaction Commit (batch mutate executed) > > Case 2. Failed update: User adds new contact > > Biz op 1. Row is created in "contacts" > Biz op 2. Row is created for SMS message queuing. Fails due to invalid > international phone number format > return op 2 > return op 1 > Transaction is rolled back (batch mutate never executed) > > > Now, here is where I can't find what I need in the doc. In case 1, if my > mutation from biz op 2 were to fail during a batch mutate operation > encapsulating all mutations, does the batch mutation as a whole not get > executed, or would I still have the mutation from op 1 written to cassandra > while the op 2 write fails? > > Thanks, >
