[theChaosCoder]

The index is just a lookup table for a field (or multiple fields). You can name it like you want. It's not really important for our case. If you query like Select .... where auth = "abc" then mysql don't need to scan the entire table but can look up the value very fast by performing something like a binary search. You can also check if an index is used by your query by adding EXPLAIN before the SELECT statement ;)

Btw, the struct.sql file (located in /install/includes) have a FULLTEXT index.

....
PRIMARY KEY (`bid`),
KEY `sid` (`sid`),
FULLTEXT KEY `reason` (`reason`),
FULLTEXT KEY `authid_2` (`authid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;


p.s. You could try to switch to innoDB if you have a recent mysql version installed. InnoDB is now very fast, ACID compatible, supports also fulltext search and is locking only the row on update / (also insert?) rather then the entire table. Also they don't really work on myisam anymore...

[friagram]

i use innodb, have index built for everything that gets compared/whered