incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <aa...@thelastpickle.com>
Subject Re: b-tree
Date Thu, 21 Jul 2011 22:01:13 GMT
> But how will you be able to maintain it while it evolves and new data is added without
transactions?

What is the situation you think you need transactions for ?

Cheers

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

On 22 Jul 2011, at 00:06, Eldad Yamin wrote:

> Aaron,
> Nested set is exactly what I had in mind.
> But how will you be able to maintain it while it evolves and new data is added without
transactions?
> 
> Thanks!
> 
> On Thu, Jul 21, 2011 at 1:44 AM, aaron morton <aaron@thelastpickle.com> wrote:
> Just throwing out a (half baked) idea, perhaps the Nested Set Model of trees would work
 http://en.wikipedia.org/wiki/Nested_set_model
> 
> * Ever row would represent a set with a left and right encoded into the key
> * Members are inserted as columns into *every* set / row they are a member. So we are
de-normalising and trading space for time. 
> * May need to maintain a custom secondary index of the materialised sets. e.g. slice
a row to get the first column >= the left value you are interested in, that is the key
for the set. 
> 
> I've not thought it through much further than that, a lot would depend on your data.
The top sets may get very big, . 
> 
> Cheers
> 
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 21 Jul 2011, at 08:33, Jeffrey Kesselman wrote:
> 
>> Im not sure if I have an answer for you, anyway, but I'm curious....
>> 
>> A b-tree and a binary tree are not the same thing.  A binary tree is a basic fundamental
data structure,  A b-tree is an approach to storing and indexing data on disc for a database.
>> 
>> Which do you mean?
>> 
>> On Wed, Jul 20, 2011 at 4:30 PM, Eldad Yamin <eldad87@gmail.com> wrote:
>> Hello,
>> Is there any good way of storing a binary-tree in Cassandra?
>> I wonder if someone already implement something like that and how accomplished that
without transaction supports (while the tree keep evolving)?
>> 
>> I'm asking that becouse I want to save geospatial-data, and SimpleGeo did it using
b-tree:
>> http://www.readwriteweb.com/cloud/2011/02/video-simplegeo-cassandra.php
>> 
>> Thanks!
>> 
>> 
>> 
>> -- 
>> It's always darkest just before you are eaten by a grue.
> 
> 


Mime
View raw message