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 chen.daqi@gmail.com
 designates 209.85.161.44 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:from:date:message-id:subject:to:content-type
         :content-transfer-encoding;
        b=NW/lXuvleBDkHL1oBIaYB6pgF6muZZIx801+n3hCgQR/XI0oj8JfGR8eBIzvXUm8n0
         tHExlh+Omg2u6pIcNnmaXc75KGBg4YC/Peg5hkyxsclJTXG0RVuBvEU0/5aBDt9M8A02
         AOFlxiJjMlNlyuVGpRp2Car1N1EMHEUsZby28=
MIME-Version: 1.0
From: Chen Xinli <chen.daqi@gmail.com>
Date: Fri, 19 Nov 2010 07:31:04 -0800
Message-ID: <-7753762334317987315@unknownmsgid>
Subject: Re: Data model design question
To: Nanheng Wu <nanhengwu@gmail.com>,
	"user@cassandra.apache.org" <user@cassandra.apache.org>
Content-Type: text/plain; charset=GB2312
Content-Transfer-Encoding: quoted-printable

=B2=E9=D1=AF=CA=C7=CD=EA=C8=AB=BB=F9=D3=DA=B5=B1=CC=EC=BC=C6=CB=E3=B5=C4=CA=
=FD=BE=DD=C2=F0 =BB=B9=CA=C7=BB=F9=D3=DA=B5=B1=CC=EC=BA=CD=C0=FA=CA=B7=CA=
=FD=BE=DD=B5=C4=BA=CF=B2=A2=A3=BF

Nanheng Wu <nanhengwu@gmail.com>=B1=E0=D0=B4=A3=BA


Hi,

 Our team decided to use Cassandra as storage solution to a dataset.
I am very new to the NoSQL world and Cassandra so I am hoping to get
some help from the community: The dataset is pretty simple, we have
for each key a number of columns with values. Each day we compute a
new version of this dataset, the new version will mostly update
existing keys but could also add and delete some keys. (And we'll
build a service that queries Cassandra). A key requirement for us is
we want to keep versions of the dataset and keep N versions around,
this is in case we discover problems in the current version and need
to "roll up" to an older one. I thought about creating a Column Family
per version, this means we will create a new column family every day
and occasionally delete column families according to some truncation
policy. I know Cassandra 0.7 now makes changing schema easier, but is
this a good way to go? I would really like to hear what you guys think
is the better way to handle this. Thank you.

Best,
Alex