Search Engine - Lucene or Solr

Question

We need to integrate a search engine in our Product Catalog management software. the catalog is expected to have more than 4-5 mn. records with relational data spread over s

Answer 1

We are exactly in the same situation as you are. Unfortunately I was not directly involved in the evaluation process, but at the end we're going to use Solr integrated with Lucene.

The main advantage is the variety of formats as dcruz described. So you can query your Solr-Consumer and get back your search result as XML data which can be easily parsed and displayed on the webpage.