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From Shahab Yunus <shahab.yu...@gmail.com>
Subject Re: Cassandra Reads
Date Fri, 06 Sep 2013 12:45:50 GMT
It only reads till that column (a sequential scan, I believe) and do not
read the whole row. It uses a row-level column index to reduce the amount
of data read.

Much more details at (first 2-3 are must-reads in fact):
http://thelastpickle.com/blog/2011/07/04/Cassandra-Query-Plans.html
http://www.datastax.com/documentation/cassandra/1.2/webhelp/index.html?pagename=docs&version=1.2&file=#cassandra/dml/dml_about_reads_c.html
http://www.roman10.net/how-apache-cassandra-read-works/
http://wiki.apache.org/cassandra/ArchitectureInternals

Regards,
Shahab


On Fri, Sep 6, 2013 at 6:28 AM, Sridhar Chellappa <schellap2009@gmail.com>wrote:

> Folks,
>
> When I read Column(s) from a table, does Cassandra read only that column?
> Or, does it read the entire row into memory and then filters out the
> contents to send only the requested column(s) ?
>

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