Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@cassandra.apache.org
Received-SPF: pass (athena.apache.org: domain of s5alye@gmail.com designates
 209.85.213.43 as permitted sender)
MIME-Version: 1.0
In-Reply-To: 
 <CAAam9svUeqBsk1A+AMDqE2p0ZiNrWMhbC1KCTvEDp0+ibcXkGg@mail.gmail.com>
References: 
 <CAGXoe2XEcP_Pus4B0V8jKahKCDWFYb_qeosCHkPCmPmHcxnfpA@mail.gmail.com>
	<DF0A4D96-C67E-4622-9956-1DE229836283@thelastpickle.com>
	<CAGXoe2UX8MoVQCLciDF+dOrZVfQtNWUMb_vTYsGmt3SKwUdbrw@mail.gmail.com>
	<CAAam9svUeqBsk1A+AMDqE2p0ZiNrWMhbC1KCTvEDp0+ibcXkGg@mail.gmail.com>
Date: Wed, 14 Mar 2012 18:22:01 -0400
Message-ID: 
 <CAGXoe2Wy5BmB1Q5oGogW_XPKRutF2CbCj9ayhxgodv6aEJ0YSw@mail.gmail.com>
Subject: Re: Does the 'batch' order matter ?
From: A J <s5alye@gmail.com>
To: user@cassandra.apache.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

> No, batch_mutate() is an atomic operation.  When a node locally applies a=
 batch mutation, either all of the changes are applied or none of them are.=
<
The steps in my batch are not confined to a single CF, nor to a single key.

The documentation says:
datastax:
Column updates are only considered atomic within a given record (row).

Pycassa.batch:
This interface does not implement atomic operations across column
families. All the limitations of the batch_mutate Thrift API call
applies. Remember, a mutation in Cassandra is always atomic per key
per column family only.


On Wed, Mar 14, 2012 at 4:15 PM, Tyler Hobbs <tyler@datastax.com> wrote:
> On Wed, Mar 14, 2012 at 11:50 AM, A J <s5alye@gmail.com> wrote:
>>
>>
>> Are you saying the way 'batch mutate' is coded, the order of writes in
>> the batch does not mean anything ? You can ask the batch to do A,B,C
>> and then D in sequence; but sometimes Cassandra can end up applying
>> just C and A,B (and D) may still not be applied ?
>
>
> No, batch_mutate() is an atomic operation.=A0 When a node locally applies=
 a
> batch mutation, either all of the changes are applied or none of them are=
.
>
> Aaron was referring to the possibility that one of the replicas received =
the
> batch_mutate, but the other replicas did not.
>
> --
> Tyler Hobbs
> DataStax
>