I need to set ft_min_word_length=3, so that my users can perform boolean fulltext searches for words of three characters instead of four. However, I share the MySQL server with other customers of my ISP.
My ISP's administrator is willing to change this system variable, provided I can show him an authoritative source that says doing so won't break anything if other customers don't rebuild their FULLTEXT indexes.
The description on http://dev.mysql.com/doc/refman/5.1/en/fulltext-fine-tuning.html contains no warnings; the text only implies that setting ft_min_word_len=3 will have no effect until you rebuild your FULLTEXT indexes (which should continue to work as they did before).
The following quote from my admin's latest email explains his problem:
Can you find any authoritative source that actually says that the only consequence is that text searches won't find any 3-character words because the fulltext index won't contain them until it's rebuilt? The MYSQL manual doesn't clearly say this, and it does say that "you must rebuild your fulltext index."
There are quite a few other MySQL databases on the server, many of them automatically created when installatron is used, and I have no idea if any of them use fulltext searches. I can't afford the risk of any of them breaking. So all I need is some authoritative source that says that existing databases will not be affected.
Anybody know of an authoritative source that explains the consequences?