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From aaron morton <aa...@thelastpickle.com>
Subject Re: Wide Row Performance & Index Question
Date Mon, 20 Feb 2012 20:28:37 GMT
this http://thelastpickle.com/2011/07/04/Cassandra-Query-Plans/

> A.) At what column count does this happen?
Based on column serialised size https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L325

> B.) If Thrift is only getting slices of a large row (column_start=X, column_end=Y, limit
20) is their any performance hits to rows over and above the A.) threshold above?
Anything with a start column, or using reverse will need to use the column index if it is
present. 

> Finally, I am correct in thinking the cluster may appear slightly unbalanced depending
on the RF and the amount of nodes with a great deal of large rows?
Yes if you have RF > cluster size. 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 21/02/2012, at 7:45 AM, Blake Starkenburg wrote:

> Question pertaining to wide or large rows in Cassandra. I recall reading in a blog I
believe posted by Aaron Morton a notation that Cassandra creates its own index of a row when
it reaches X amount of columns? My curiosity is: 
> 
> A.) At what column count does this happen?
> B.) If Thrift is only getting slices of a large row (column_start=X, column_end=Y, limit
20) is their any performance hits to rows over and above the A.) threshold above?
> 
> Finally, I am correct in thinking the cluster may appear slightly unbalanced depending
on the RF and the amount of nodes with a great deal of large rows?
> 
> note: using php_cassa & Cassandra 0.8.10
> 
> Thanks!


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