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From Fabian Siddiqi <>
Subject Re: Arbitrary nested tree hierarchy data model
Date Fri, 27 Mar 2015 08:45:24 GMT
Hi Robert,

We're trying to do something similar to the OP and finding it a bit
difficult. Would it be possible to provide more details about how you're
doing it?


On Fri, Mar 27, 2015 at 3:15 AM, Robert Wille <> wrote:

> I have a cluster which stores tree structures. I keep several hundred
> unrelated trees. The largest has about 180 million nodes, and the smallest
> has 1 node. The largest fanout is almost 400K. Depth is arbitrary, but in
> practice is probably less than 10. I am able to page through children and
> siblings. It works really well.
> Doesn’t sound like its exactly like what you’re looking for, but if you
> want any pointers on how I went about implementing mine, I’d be happy to
> share.
> On Mar 26, 2015, at 3:05 PM, List <> wrote:
> > Not sure if this is the right place to ask, but we are trying to model a
> user-generated tree hierarchy in which they create child objects of a root
> node, and can create an arbitrary number of children (and children of
> children, and on and on).  So far we have looked at storing each tree
> structure as a single document in JSON format and reading/writing it out in
> it's entirety, doing materialized paths where we store the root id with
> every child and the tree structure above the child as a map, and some form
> of an adjacency list (which does not appear to be very viable as looking up
> the entire tree would be ridiculous).
> >
> > The hope is to end up with a data model that allows us to display the
> entire tree quickly, as well as see the entire path to a leaf when
> selecting that leaf.  If anyone has some suggestions/experience on how to
> model such a tree heirarchy we would greatly appreciate your input.
> >

Fabian Siddiqi
Software Engineer
T: (+44) 776 335 1398

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