SET pg_trgm.word_similarity_threshold TO 0.2; lowers the threshold for current session but does not do it for database. I need to lower the threshold for supporting spelling mistakes.
Like the documentation says, there are two options to change the value globally (for the whole database cluster):
Add the parameter to postgresql.conf
and run pg_ctl reload
.
Run ALTER SYSTEM SET pg_trgm.word_similarity_threshold = 0.2;
and SELECT pg_reload_conf();
.
If you want to change it for a specific database, you can use
ALTER DATABASE mydb SET pg_trgm.word_similarity_threshold = 0.2;
The new setting will then be effective for all new connections.