Thanks Aaron!
On 6/22/2011 5:25 PM, aaron morton wrote:
Atomic on a single machine yes.
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com
On 23 Jun 2011, at 09:42, AJ wrote:
On 4/9/2011 7:52 PM, aaron morton wrote:
My understanding of what they did with locking (based on the examples) was to achieve
a level of transaction isolation
http://en.wikipedia.org/wiki/Isolation_(database_systems)<http://en.wikipedia.org/wiki/Isolation_%28database_systems%29>
I think the issue here is more about atomicity
http://wiki.apache.org/cassandra/FAQ#batch_mutate_atomic
We cannot guarantee that all or none of the mutations in your batch are
completed. There is some work in this area though
https://issues.apache.org/jira/browse/CASSANDRA-1684
Just to be clear, you are speaking in the general sense, right? The batch
mutate link you provide says that in the case that ALL the mutates of the batch
are for the SAME key (row), then the whole batch is atomic:
"As a special case, mutations against a single key are atomic but not
isolated."
So, is it true that if I want to update multiple columns for one key, then it
will be an all or nothing update for the whole batch if using batch update?
But, if your batch mutate containts mutates for more than one key, then all the
updates for one key will be atomic, followed by all the updates for the next
key will be atomic, and so on. Correct?
Thanks!
