The first step is to generate an auxiliary table containing all

the unique words in the Tsearch2 index:

CREATE TABLE words AS

SELECT word FROM stat('SELECT vector FROM documents');

Where 'documents' is the table that contains the Tsearch2 index

column 'vector', of type 'tsvector'.

CREATE TABLE words AS SELECT word FROM

stat('SELECT to_tsvector(''simple'', bodytext) FROM documents');

Where 'documents' is a table that has a text field 'bodytext'

that TSearch2 is used to search. The use of the 'simple' dictionary

with the to_tsvector function, instead of just using the already

existing vector is to avoid creating a list of already stemmed

words. This way, only the original, unstemmed words are added

to the word list.

Next, create a trigram index on the word column: