In J. monoadesivi With database MySQL and any other ODBC.
Raised and the Sphinx and Ya, of course Ya have relevance With the above, but he takes too long to index the site from 450,000 pages approximate time — 2 hours, and during indexing he needs 2 gig on the screw that was free(number of pages). And when he starts to merge the indexes, the server is hung up, the host complained constantly that my server eats more operatives than you(2giga). In short, You decide, but with 4M articles I would if put With Ya, on a separate server.