I've created custom index for my forum (because fulltext index gets strange results, completely ignoring some words), but it's not refreshed/updated automatically. I have to delete and create new index every few days to allow users to correctly search in all (new) topics (because relevant search is critical for use of my forum).
forum (SMF 1.1.9) has 5000+ posts and Large custom index is over 6MB big.
Is this a bug (or feature?) or did I miss some settings?
Welcome to SMF.
Try using this search mod (http://custom.simplemachines.org/mods/index.php?mod=887) and test it out a few days to see if the results are better.