That's what we planned to do in 2,0 version, and the db is organised to do this.RE: [Koha-devel] full text search Think Pick.
I don't know whether MySQL can do it, but can you create a virtual column containing all consecutive character strings, and index on that? Your free text search would need to search on whole words in that case, but the result would be very fast, and *should* be database independent.
-- Paul POULAIN Consultant indépendant en logiciels libres responsable francophone de koha (SIBGB libre http://fr.koha.org)