Tutorial Statistical Graph Analysis by Aapo Kyrola.
From the post:
GraphChi-DB can be used for efficiently querying induced subgraphs from very large networks. Thus, you can for example, easily sample a vertex, and retrive induced neighborhood graph of the vertex. Or you can choose a random set of vertices and compute their induced subgraph.
Assuming you have the data loaded in database, and the GraphChiDatabase object in a value “DB”, here is how you request edges for the induced subgraph of a set of vertices:
GraphChi-DB is released two days ago, GraphChi-DB [src released] and today you have a tutorial written for it.
Not bad, not bad at all.