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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Sparse vs dense index
Date Wed, 17 Mar 2010 13:52:22 GMT
I guess if you are going to read the full 5MB at once then that makes
more sense.

But if you are going to slice it or access parts by column name then
the other does.

On Tue, Mar 16, 2010 at 12:15 PM, alex kamil <alex.kamil@gmail.com> wrote:
> which index structure would fit Cassandra more naturally and perform better:
> 1) a sparse index where in each row there are 100 columns each containing a
> 5MB data block (under a single column family)
> or
> 2) a dense index where  each row contains 100 columns with a single 6bytes
> value (under a single column family)
>
> - assuming the total data size is 30-50TB, 500GB appends per day
> -  the data is time series (output from a multichannel EEG sensor)
> the key performance metric for us is read throughput (random reads/sec,
> range queries, sequential scans)
>
> Thanks
> Alex
>

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