Re: Queries slow down daily, optimizing helps -> why?

[aftab khan]

>So it looks like a caching problem? Or is it a I/O problem?
it could be caching problem. we don't know how busy is your database system. You might need to use multiple key cache, preload indexes of that particualr table
Have you heard about mutiple key cache,
I suggest you should read it http://dev.mysql.com/doc/refman/5.0/en/multiple-key-caches.html
e.g.CACHE INDEX t1 IN hot_cache;
while FULLTEXT searches only returning anything if the number of results is less than 50%.