incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Ellis <jbel...@gmail.com>
Subject Re: batch_mutate atomicity
Date Sat, 07 Aug 2010 13:26:57 GMT
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.

On Sat, Aug 7, 2010 at 12:50 AM, james anderson <james.anderson@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 <bburruss@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

Mime
View raw message