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
