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From Marcelo Elias Del Valle <mvall...@gmail.com>
Subject Re: Is Cassandra right for me?
Date Tue, 18 Sep 2012 13:52:45 GMT
I will have just 6 columns in my CF, but I will have about a billion writes
per hour. In this case, I think Cassandra applies then, by what you are
saying.
This answer helped a lot too, thanks!

2012/9/18 Hiller, Dean <Dean.Hiller@nrel.gov>

> I wanted to clarify the where that statement comes from on wide rows ….
>
> Realize some people make the claim that if you don’t' have 1000's of
> columns in "some" rows in cassandra you are doing something wrong.  This is
> not true, BUT it comes from the fact that people are setting up indexes.
>  This is what leads to the very wide row affect.  playOrm is one such
> library using wide rows like this BUT it is NOT necessary for all
> applications.
>
> You can easily use map/reduce on a cassandra cluster.  You can map/reduce
> your dataset into a new model if you make a mistake as well and don't get
> it right the first time.  This wide row affect is 80% of the time used for
> indexing.  I draw off playOrm examples a lot but one table may be
> partitioned by time so each month of data is in a partition, you can then
> have indexes on each partition allowing you to do quick queries into
> partitions.
>
> Later,
> Dean
>
> From: Marcelo Elias Del Valle <mvallebr@gmail.com<mailto:
> mvallebr@gmail.com>>
> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Date: Monday, September 17, 2012 4:28 PM
> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Subject: Is Cassandra right for me?
>
> Hello,
>
>      I am new to Cassandra and I am in doubt if Cassandra is the right
> technology to use in the architecture I am defining. Also, I saw a
> presentation which said that if I don't have rows with more than a hundred
> rows in Cassandra, whether I am doing something wrong or I shouldn't be
> using Cassandra. Therefore, it might be the case I am doing something
> wrong. If you could help me to find out the answer for these questions by
> giving any feedback, it would be highly appreciated.
>      Here is my need and what I am thinking in using Cassandra for:
>
>  *   I need to support a high volume of writes per second. I might have a
> billion writes per hour
>  *   I need to write non-structured data that will be processed later by
> hadoop processes to generate structured data from it. Later, I index the
> structured data using SOLR or SOLANDRA, so the data can be consulted by my
> end user application. Is Cassandra recommended for that, or should I be
> thinking in writting directly to HDFS files, for instance? What's the main
> advantage I get from storing data in a nosql service like Cassandra, when
> compared to storing files into HDFS?
>  *   Usually I will write json data associated to an ID and my hadoop
> processes will process this data to write data to a database. I have two
> doubts here:
>     *   If I don't need to perform complicated queries in Cassandra,
> should I store the json-like data just as a column value? I am afraid of
> doing something wrong here, as I would need just to store the json file and
> some more 5 or 6 fields to query the files later.
>     *   Does it make sense to you to use hadoop to process data from
> Cassandra and store the results in a database, like HBase? Once I have
> structured data, is there any reason I should use Cassandra instead of
> HBase?
>
>      I am sorry if the questions are too dummy, I have been watching a lot
> of videos and reading a lot of documentation about Cassandra, but honestly,
> more I read more I have questions.
>
> Thanks in advance.
>
> Best regards,
> --
> Marcelo Elias Del Valle
> http://mvalle.com - @mvallebr
>



-- 
Marcelo Elias Del Valle
http://mvalle.com - @mvallebr

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