I have a MyISAM table in a MySQL database on an Ubuntu 10.04 server with 256mb RAM. Maximum packet size is 32mb. The table has 150,000 rows.
The table has three columns, two of which are TEXT type. I create a FULLTEXT index on both of these; one index has cardinality equal to the number of rows in the table, the other only one third.
Why is that?
Does a low-cardinality index imply MATCH() AGAINST() will miss hits? (It seems so.) If so, can I increase a memory limit some where to increase the cardinality of my index?