What Mongo Index algorithm is using? Binary Tree?

Question

I would like to know what kind of internal indexing algorithm MongoDB is using. Because I have some data want to store, and each document (row) has a id, which is probably a unique hash value. (e.g. generated by md5() or other hash algorithm). so, I would to understand which hash method I should use to create the id, so that it is fast for the MongoDB to index it. :)

Answer 1

Yes, mongoDB use b-tree, documentation:

An index is a data structure that collects information about the values of the specified fields in the documents of a collection. This data structure is used by Mongo's query optimizer to quickly sort through and order the documents in a collection. Formally speaking, these indexes are implemented as "B-Tree" indexes.

I suggest to use mongodb ObjectId for collection _id, and don't care about: "How to create _id?" at all. Because it probably task for mongodb, but not for developer. I suppose that better to care about schema, indexes, etc..