I use PostgreSQL 9.4.
I have a database where a table have index in column which can contains two possible value only(gender: male/female). When I execute a query with condition on this column index was not use. It's bad idea use index in such column?
If index useless in this case, will I have update for this index when add new record. In other words: Will I have increase insert speed if I remove this index?
SQL for index:
CREATE INDEX index_participations_on_gender ON participations USING btree (gender COLLATE pg_catalog."default");
SELECT participations.last_name, participations.first_name, participations.birthday, participations."number", participations.chip_id, participations.gender FROM public.participations WHERE participations.gender = 'male';
Rows in the table: 64982