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From sridhar basam <...@basam.org>
Subject Re: Modeling troubles
Date Thu, 21 Jul 2011 15:07:46 GMT
On Thu, Jul 21, 2011 at 9:18 AM, Stephen Pope <Stephen.Pope@quest.com>wrote:

>  For a side project I’m working on I want to store the entire set of
> possible Reversi boards. There are an estimated 10^28 possible boards. Each
> board (from the best way I could think of to implement it) is made up of 2,
> 64-bit numbers (black pieces, white pieces…pieces in neither of those are
> empty spaces) and a bit to indicate who’s turn it is. I’ve thought of a few
> possible ways to do it:****
>
> ** **
>
> **-          **Entire board as row key, in an array of bytes. I’m not sure
> how well Cassandra can handle 10^28 rows. I could also break this up into
> separate cfs for each depth of move (initially there are 4 pieces on the
> board in total. I could make a cf for 5 piece, 6, etc to 64). I’m not sure
> if there’s any advantage to doing that.****
>
> **-          **64-bit number for the black pieces as row key, with 65-bit
> column names (white pieces + turn). I’ve read somewhere that there’s a rough
> limit of 2-billion columns, so this will be problematic for certain. This
> can also be broken into separate cfs, but I’m still going to hit the column
> limit****
>
> ** **
>
> Is there a better way to achieve what I’m trying to do, or will either of
> these approaches surprise me and work properly?****
>

Short answer, it is just not possible to store or even compute the kind of
information you want to. You can do the math on how many years/centuries it
would take to compute that many combinations no to mention what it would
take to store on the order of 1000 YB.

 sridhar

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