Creating a noSql database, what is the best source code to look at?

Question

I have always wanted a nosql database that was purpose built for storing large volumes of nested/threaded comments. Implementation would probably be done in java because that is what I am best at. I really like how ElasticSearch is dead simple to set up a cluster and throw data into it, I want my product to share those same qualities. Here are the features I have in mind:

1) auto/manual sharding across clusters
2) auto/manual indexing across clusters
3) full text search (probably via lucene or elasticSearch)
4) REST/JSON API
5) retrieve any comment by ID
6) comments can be retrieved with or without child nodes
7) comment trees can be retrieved with a specified depth
8) comment tree can be retrieved can be filtered by time or rank
9) entire comment trees can be re-parented.

What I'm looking for are exceptional pieces of code or specific algorithms that I can study before digging into this project. Can anyone suggest a few places to get started?

Answer 1

Since your tag in a question indicates Java, I suggest looking into OrientDB.

Here is a source code:

http://code.google.com/p/orient/source/browse/

and the architecture:

http://code.google.com/p/orient/wiki/Presentations

for the big boy stuff (clustering, hyper scaling take a look at HBase and Accumulo):

http://hbase.apache.org/source-repository.html

http://accumulo.apache.org/source.html

Hope this helps.
Edmon