Install pg_trgm in PostgreSQL 8.4 on Windows XP I just tried to enter in psql shell as user postgres:
&gt; psql -U postgres

then connect to my database
&gt; \c MyDATA

and then try to execute this command to install similarity function from pg_trgm
&gt; \i c:/postgresql/8.4/share/contrib/pg_trgm.sql

I got this result, and seems not to be working:
SET
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE OPERATOR
psql:c:/postgresql/8.4/share/contrib/pg_trgm.sql:44: NOTICE:  el tipo Â«gtrgmÂ»
no ha sido definido aÃºn
DETALLE:  Creando una definiciÃ³n de tipo inconclusa.
CREATE FUNCTION
psql:c:/postgresql/8.4/share/contrib/pg_trgm.sql:49: NOTICE:  el tipo de argumen
to gtrgm estÃ¡ inconcluso
CREATE FUNCTION
CREATE TYPE
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE OPERATOR CLASS
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE OPERATOR CLASS

Is probably something that I have been missing, but I don't know what?
Is this the correct way to install it in 8.4 under XP? (I can't change OS).
Answered in comments by a-horse-with-no-name:

Those are only &quot;notice&quot; message, not errors (I don't understand what they say, but NOTICE is never a problem or even an error). All statements ran without error, so everything is fine and the module was created. But you should really upgrade to a modern version (12 or 13) and also ditch Windows XP.