full text search index

Hi there,

I've got the following query:

SELECT COUNT(DISTINCT j0_.id) AS sclr10
FROM customers j0_
WHERE ((LOWER(j0_.name_first) LIKE '%some%'
        OR LOWER(j0_.name_last) LIKE '%some%')       
       AND j0_.id = 5)
  AND j0_.id = 5

The query is taking ages to run.

I read about wildcards and it seems I have to use a function with to_tsvector ? 

CREATE INDEX CONCURRENTLY ON public.customers USING gin ("clientid", ("full_text_universal_cast"("name_first"::"text")), ("full_text_universal_cast"("name_last"::"text")));

full_text_universal_cast:

CREATE OR REPLACE FUNCTION public.full_text_universal_cast(doc_data "text")
  RETURNS "tsvector" AS
$BODY$
SELECT to_tsvector('english', COALESCE(TRIM(CAST(doc_data AS TEXT)), ''));
$BODY$
  LANGUAGE sql IMMUTABLE
  COST 1000;

Would be something like above? Because it's not working...

What am I missing guys?

Thanks