contrib/pg_trgm/sql/pg_word_trgm.sql

CREATE TABLE test_trgm2(t text COLLATE "C");

\copy test_trgm2 from 'data/trgm2.data'

-- reduce noise
set extra_float_digits = 0;

select t,word_similarity('Baykal',t) as sml from test_trgm2 where 'Baykal' <% t order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where 'Kabankala' <% t order by sml desc, t;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where t %> 'Baykal' order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where t %> 'Kabankala' order by sml desc, t;
select t <->> 'Kabankala', t from test_trgm2 order by t <->> 'Kabankala' limit 7;

create index trgm_idx2 on test_trgm2 using gist (t gist_trgm_ops);
set enable_seqscan=off;

select t,word_similarity('Baykal',t) as sml from test_trgm2 where 'Baykal' <% t order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where 'Kabankala' <% t order by sml desc, t;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where t %> 'Baykal' order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where t %> 'Kabankala' order by sml desc, t;

explain (costs off)
select t <->> 'Kabankala', t from test_trgm2 order by t <->> 'Kabankala' limit 7;
select t <->> 'Kabankala', t from test_trgm2 order by t <->> 'Kabankala' limit 7;

drop index trgm_idx2;
create index trgm_idx2 on test_trgm2 using gin (t gin_trgm_ops);
set enable_seqscan=off;

select t,word_similarity('Baykal',t) as sml from test_trgm2 where 'Baykal' <% t order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where 'Kabankala' <% t order by sml desc, t;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where t %> 'Baykal' order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where t %> 'Kabankala' order by sml desc, t;

set "pg_trgm.word_similarity_threshold" to 0.5;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where 'Baykal' <% t order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where 'Kabankala' <% t order by sml desc, t;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where t %> 'Baykal' order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where t %> 'Kabankala' order by sml desc, t;

set "pg_trgm.word_similarity_threshold" to 0.3;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where 'Baykal' <% t order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where 'Kabankala' <% t order by sml desc, t;
select t,word_similarity('Baykal',t) as sml from test_trgm2 where t %> 'Baykal' order by sml desc, t;
select t,word_similarity('Kabankala',t) as sml from test_trgm2 where t %> 'Kabankala' order by sml desc, t;

-- test unsatisfiable pattern
select * from test_trgm2 where t ~ '.*$x';