[BUGS] pg_trgm word_similarity inconsistencies or bug
| От | Cristiano Coelho |
|---|---|
| Тема | [BUGS] pg_trgm word_similarity inconsistencies or bug |
| Дата | |
| Msg-id | CY4PR17MB13207ED8310F847CF117EED0D85A0@CY4PR17MB1320.namprd17.prod.outlook.com обсуждение исходный текст |
| Ответы |
Re: [BUGS] pg_trgm word_similarity inconsistencies or bug
|
| Список | pgsql-bugs |
Hello all, this is related to postgres 9.6 (9.6.4) and a good description can be found here https://stackoverflow.com/questions/46966360/postgres-word-similarity-not-comparing-words
But in summary, word_similarity doesn’t seem to do exactly what the docs say, since it will match trigrams from multiple words rather tan doing a word by word comparison.
Below is a table with output and expected output, thanks to kiln from stackoverflow to provide it.
with data(t) as (
values ('message'),
('message s'),
('message sag'),
('message sag sag'),
('message sag sage')
) select t, word_similarity('sage', t), my_word_similarity('sage', t)
from data;
t | word_similarity | my_word_similarity
------------------+-----------------+-------------------- message | 0.6 | 0.3
message s | 0.8 | 0.3
message sag | 1 | 0.5
message sag sag | 1 | 0.5
message sag sage | 1 | 1
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