Merge

@cindex searching, full-text

@cindex full-text search

@cindex FULLTEXT

@node MySQL full-text search,  , MySQL threads, MySQL internals

@section MySQL Full-text Search

with search engine), and, as such, has low semantical value in @strong{this

particular dataset}.

@menu

* Fine-tuning::

@end menu

@node Fine-tuning, , , MySQL full-text search

Unfortunately, full-text search has no user-tunable parameters yet

(but adding some is very high in our TODO). But if one has @strong{MySQL}

source distribution (@xref{Installing source}.) he can somewhat alter

full-text search default behaviour.

But note, that full-text search was carefully tuned up for the best

search effectivity. Modifying default behaviour will, most probably,

make search results only worse. Do not play with @strong{MySQL} sources,

unless you know what you are doing!

@itemize

@item

Minimal length of word to be indexed is defined in

@code{myisam/ftdefs.h} file by the line

@example

#define MIN_WORD_LEN 4

@end example

Change it to the value, you prefer, recompile @strong{MySQL} and rebuild

your @code{FULLTEXT} indexes.

@item

Stopword list is defined in @code{myisam/ft_static.c}

Modify it to your taste, recompile @strong{MySQL} and rebuild

your @code{FULLTEXT} indexes.

@item

50% treshold is caused by weighting scheme chosen. To disable it, change

@example

#define GWS_IN_USE GWS_PROB

@end example

line in @code{myisam/ftdefs.h} to

@example

#define GWS_IN_USE GWS_IDF

@end example

and recompile @strong{MySQL}.

There is no need to rebuild the indexes though.

@end itemize

@page

@cindex environment variables, list of

@node Environment variables, Users, MySQL internals, Top

Responsible for @strong{MySQL} configure.

@end itemize

@item Sergei A. Golubchik

@item Sergei Golubchik

@itemize @bullet

@item

Text search

Full-text search

@item

Added keys to the @code{MERGE} library.

@end itemize