FORCE_INDEX is not the right way to optimize the query only a compromise.
Did you add my index suggestion on table NODE and TERM_NODE?
I try to optimize this query from your first message:
EXPLAIN
SELECT node.nid AS nid, node.created AS node_created, node.title AS node_title
FROM node node
INNER JOIN term_node term_node ON node.vid = term_node.vid
WHERE
node.type IN ('news')
AND node.STATUS <>0
AND term_node.tid =10
ORDER BY node_created DESC
LIMIT 0 , 3
About your question:
2) Index is faster than filesort
First please try my Index hints.
ALTER TABLE term_node
DROP KEY vid,
DROP KEY tid,
ADD KEY idx_vid_tid (vid,tid),
ADD KEY idx_tid_vid (tid,vid);
ALTER TABLE node
DROP KEY node_type,
ADD KEY idx_type_status_vid (type(4), status, vid);
with kind regards,
Thomas