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List:       cassandra-dev
Subject:    Re: Row vs CF
From:       Jonathan Ellis <jbellis () gmail ! com>
Date:       2009-04-24 17:49:47
Message-ID: e06563880904241049y7f6b04deq74f93a4d9c49e6ca () mail ! gmail ! com
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I'm unconvinced on both counts -- that analytics somehow implies that
CF locality is no longer important, and that doing a request per CF
would be unacceptable.

On Fri, Apr 24, 2009 at 12:13 PM, Jun Rao <junrao@almaden.ibm.com> wrote:
> There are definitely cases that you want to read a full row. For example,
> for some batch jobs that do analytics.
>
> In fact, Table used to have a method that reads a full row and it's used =
in
> test.DataImporter. Apparently, that code is broken now.
>
> Jun
> IBM Almaden Research Center
> K55/B1, 650 Harry Road, San Jose, CA 95120-6099
>
> junrao@almaden.ibm.com
>
> Jonathan Ellis <jbe@familyellis.org>
>
>
> Jonathan Ellis <jbe@familyellis.org>
> Sent by: jbellis@gmail.com
>
> 04/22/2009 08:54 AM
>
> Please respond to
> cassandra-dev@incubator.apache.org
>
> To
> cassandra-dev@incubator.apache.org
> cc
>
> Subject
> Row vs CF
>
> In a bunch of places in the code we wrap a CF in a Row object,
> basically a key + multiple CFs. =A0But currently only a single
> ColumnFamily will ever be in a Row object. =A0(At least in the Rows
> involved in a client read op. =A0Maybe Rows are used internally in other
> places with multiple CFs. =A0But I am concerned with the read path
> here.)
>
> Is this an example where we should apply YAGNI?
> (http://en.wikipedia.org/wiki/You_Ain%27t_Gonna_Need_It) =A0It seems to
> me that if the definition of a CF is, "this is data that is logically
> or otherwise related" then adding an API to request multiple CFs at
> once is unnecessary. =A0(If you really need data from multiple CFs
> frequently, your data model is broken and you should combine the CFs;
> if you need it infrequently, the overhead from doing multiple queries
> is not a big deal.)
>
> Thoughts?
>
> -Jonathan
>
>


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