>Such search cannot be optimized by full-text or any other indexes and will require full table scan. You may use regular LIKE '%iche%'.

Thanks, I have found that sometimes the client is in need of searching for something in which he doesn't know what it starst with or what it ends with. So, in those particular situations, I would then use a syntax as you suggested. This means there is no way to optimize that. We will probably have a validation to force the selection of an additional field that is fully optimized in order to speed that query and have that search to fall in a sub search.