Re: Index ot being used

Madison Kelly <linux(at)alteeve(dot)com> writes:
> Here is my full query:

> tle-bu=> EXPLAIN ANALYZE SELECT file_name, file_parent_dir, file_type
> FROM file_info_7 WHERE file_type='d' ORDER BY file_parent_dir ASC,
> file_name ASC;

> This is my index (which I guess is wrong):

> tle-bu=> \d file_info_7_display_idx
> Index "public.file_info_7_display_idx"
> Column | Type
> -----------------+----------------------
> file_type | character varying(2)
> file_parent_dir | text
> file_name | text
> btree, for table "public.file_info_7"

The index is fine, but you need to phrase the query as

... ORDER BY file_type, file_parent_dir, file_name;

(Whether you use ASC or not doesn't matter.) Otherwise the planner
won't make the connection to the sort ordering of the index.

regards, tom lane