The first.
On Sat, Aug 7, 2010 at 10:04 AM, james anderson <james.ander...@setf.de> wrote: > good afternoon; > > On 2010-08-07, at 15:26 , Jonathan Ellis wrote: > >> I am using the familiar meanings from ACID: >> >> atomic means either the entire update will succeed or none of it. >> >> isolated means other threads will not see partial updates while it is >> being applied. > > yes, those terms are not new. > > it remains, that the answer with respect to isolation would be clearer were > it expressed in terms of cassandra's operations. given the two-level map > passed to batch_mutate, > > is it that another thread could see the effect of some mutation object in > one entry of the inner key map, but not see the effect of some other > mutation object in the same entry of the inner key map? > > or > > is it that another thread could see the effect of one set of mutation > objects in one entry of the inner key map, but not see the effect of some > other set of mutation object in a different entry of the inner key map? > > which one? > >> >> On Sat, Aug 7, 2010 at 12:50 AM, james anderson <james.ander...@setf.de> >> wrote: >>> >>> good morning; >>> >>> On 2010-08-07, at 02:45 , Jonathan Ellis wrote: >>> >>>> Everything in the same key of a batch_mutate is atomic. (But not >>>> isolated.) >>>> >>> >>> what does the distinction mean in the context of cassandra? >>> is it that the execution of an operation with the same key could see the >>> effect of the 'first' mutation on one column family but not another, or >>> that >>> they could see the presence/absence of some columns in a row, but not >>> others, or? >>> >>> would it be possible to illustrate the difference with some simple >>> examples. >>> >>>> On Fri, Aug 6, 2010 at 2:15 PM, B. Todd Burruss <bburr...@real.com> >>>> wrote: >>>>> >>>>> ok i just saw the FAQ >>>>> (http://wiki.apache.org/cassandra/FAQ#batch_mutate_atomic) >>>>> >>>>> follow up question ... >>>>> >>>>> it states that "As a special case, mutations against a single key are >>>>> atomic, but more generally no" ... i interpret that to also mean " .. >>>>> mutations against a single key in the same CF ... " >>>>> >>>>> so if i have several mutatations against a single key, but multiple >>>>> column families i assume this is not atomic? >>>>> >>>>> thx >>>>> >>>>> >>>>> On Fri, 2010-08-06 at 11:08 -0700, Todd Burruss wrote: >>>>>> >>>>>> if i am using batch_mutate to update/insert two columns in the same CF >>>>>> and same key, is this an atomic operation? >>>>>> >>>>>> i understand that an operation on a single key in a CF is atomic, but >>>>>> not sure if the above scenario boils down to two operations or >>>>>> considered one operation. >>>>>> >>>>>> thx >>>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> -- >>>> Jonathan Ellis >>>> Project Chair, Apache Cassandra >>>> co-founder of Riptano, the source for professional Cassandra support >>>> http://riptano.com >>> >>> >> >> >> >> -- >> Jonathan Ellis >> Project Chair, Apache Cassandra >> co-founder of Riptano, the source for professional Cassandra support >> http://riptano.com > >
