Garlic
April 6, 2009, 7:29pm
1
What is the importance of ft_query_expansion_limit and what exactly it’s doing?
from http://dev.mysql.com/doc/refman/5.0/en/server-system-variabl es.html
[B]Quote:[/B]
The number of top matches to use for full-text searches performed using WITH QUERY EXPANSION.
I don't unerstand what they mean by that.
vgatto
April 6, 2009, 8:54pm
2
Basically, query expansion performs a full text search and then uses the first few results (configured by ft_query_expansion_limit) to search again and compose your result set. The explanation in the docs is probably better than mine:
http://dev.mysql.com/doc/refman/5.1/en/fulltext-query-expans ion.html
Garlic
April 6, 2009, 9:31pm
3
Does increasing this value improves performance?
vgatto
April 7, 2009, 12:17am
4
Unless you are specifically using WITH QUERY EXPANSION in your fulltext queries, this will have no affect on performance.
Garlic
April 7, 2009, 2:38am
5
Thanks. I’ll remember that.