Sounds like quite a few NoSQL projects are externalizing the full text indexing to either Lucene or Solr (take for example CouchDB integration with Lucene or Neo4j integration with Lucene and Solr).

Now even if there are some basic ways (see ^[1] and ^[2]) to achieve this with MongoDB alone, people are still looking for more scalable solutions as shown by this thread ☞ covering Solr integration with MongoDB. The thread also mentions a couple of existing Ruby or Rails plugins for this integration.

One concern that I’ve expressed about the integration with Lucene alone is that you’ll have to deal with its scalability. Solr is one way to do that automatically. Lately I have heard of a new solution for scalable search: ☞ ElasticSearch which sounds quite interesting (nb: I haven’t yet gone through its docs or played with it, but the creator of the project has a long search/indexing history behind. You can find more details about Elastic Search here^[3]).

In a previous post, I was writing that Neo4j, as CouchDB, is using Lucene for full text indexing. While agreeing that this is definitely better than reinventing the wheel, I was also raising my concern about the complexity and scalability of this approach.

Now it looks like there is some work to integrate Neo4j with Solr, the standalone full-text search server based on Lucene ^[1]. This would definitely address the issue I have raised. Anyway it is not yet clear from the original message ^[2] how this integration will work though (it sounds like a two-way integration, but I may be misinterpreting the details). The code is availalbe on Neo4j ☞ SVN.