RavenDB and implementing AStar pathfinding algorithm within the map/reduce step?

[Utunga]

Hello,

I have an application where I have a bunch of data about people, and
want to manipulate that in a crud type way, but I also want to find
paths through the 'friend graph' of those people.

The obvious way to find such paths is something like the A-Star
algorithm. (Nicely summarized here: http://www.policyalmanac.org/games/aStarTutorial.htm)

I haven't read this fully yet, but according to this article -
http://blogs.vertigo.com/personal/rtaylor/Blog/Lists/Posts/Post.aspx?ID=4
it is also possible to implement AStar leveraging LINQ.

At small scale there is no problem as we simply load all nodes into
memory, but curious whether at a medium to large scale, if we had a
case where we wanted to calculate many paths in reasonable time,
whether RavenDB might have any advantages.

Specifially I wonder about whether it would be doable to implement
something like AStar inside of the map/reduce phases of an index.

Any thoughts or suggestions on this would be appreciated. If there are
suggestions for tools other than RavenDB that might be better suited
for this task I'd appreciate that also - as I haven't yet finalized on
what DB technology to use for this project.

Thanks for all the great work you do.

[Oren Eini (Ayende Rahien)]

That is hard to answer given the information provided.

Let us start by thinking what you actually want. You want to generate a path from all nodes to all other nodes.

That isn't a map/reduce operation, because this isn't map/reduce anything. You actually need the entire data set for the work to happen, there isn't really a good way to split things up