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From "Dop Sun" <su...@dopsun.com>
Subject RE: How many KeySpace will you use in a single application?
Date Sat, 10 Apr 2010 14:49:51 GMT
So, if my understanding is correct, in this case, the small replication factor key space is
a online back system, or BCP environment. :)

Very good one. Actually, one of the things which make me a little bit uncomfortable is BCP:
once something goes wrong, how to take it back? In the traditional RDBS world, there are lot
of documented practices and procedures to follow to make it happen. As a relative new and
improving technology, these stuff is very limited. (even google cannot help at the moment.
:-))

Regards,
Dop

-----Original Message-----
From: Benoit Perroud [mailto:benoit@noisette.ch] 
Sent: Saturday, April 10, 2010 5:48 PM
To: user@cassandra.apache.org
Subject: Re: How many KeySpace will you use in a single application?

One point in using several keyspaces is that replication factor is per keyspace.

If you have a part of your application which generate a lot of data
whoss can be lost (some non critical logs?), then a dedicated keyspace
with a smaller replication factor can be a good thing.

Kind regards,

Benoit.

2010/4/10 Dop Sun <sunht@dopsun.com>:
> Hi, a question troubles me now: how many KeySpaces one application is better
> to use?
>
>
>
> The question is coming out since 0.6, Cassandra introduced a new API named
> as “login”, which is done against a specific keySpace. Thanks to the
> org.apache.cassandra.auth.AllowAllAuthenticator, the old version clients can
> still work without authentication.
>
>
>
> Actually, while I’m working with the previous version, I just take the
> KeySpace as another level of the whole structure, KeySpace – ColumnFamily –
> Super Column (optional) – Column – Value.  And consider the whole Cassandra
> cluster as the root of all these, and one application controls everything
> under this cluster.
>
>
>
> Now, looks like I need to re-think this and put the KeySpace as a kind of
> root. It may be better to make one application only takes one KeySpace (a
> silly question? Since all old time, one application usually uses only one
> database, but forgive me, I may abuses the flexibility of Cassandra.)? Is
> there any pros or cons to user multiple key spaces vs. single key spaces,
> other than the authentication requirements?
>
>
>
> Can anyone give me some suggestions on this?
>
>
>
> Dop



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