Re: Index ot being used

On Sun, Jun 12, 2005 at 22:00:01 -0500,
  Bruno Wolff III <bruno@wolff.to> wrote:
> On Sun, Jun 12, 2005 at 18:52:05 -0400,
>   Madison Kelly <linux@alteeve.com> wrote:
> >
> >   After sending that email I kept plucking away and in the course of
> > doing so decided that I didn't need to return the 'file_type' column.
> > Other than that, it would see my query now matches what you two have
> > recommended in the 'ORDER BY...' front but I still can't get an index
> > search.
>
> No it doesn't. Even if you don't return file_type you still need it
> in the order by clause if you want postgres to consider using your
> index.

I didn't notice that you had changed the index. The reason this index
doesn't help is that you can't use it to select on records with the
desired file_type.

>
> Is there some reason you didn't actually try out our suggestion, but are
> now asking for more advice?
>
> >
> >   Here is the latest query and the new index:
> >
> > tle-bu=> \d file_info_7_display_idx;
> > Index "public.file_info_7_display_idx"
> >      Column      | Type
> > -----------------+------
> >  file_parent_dir | text
> >  file_name       | text
> > btree, for table "public.file_info_7"
> >
> > tle-bu=> EXPLAIN ANALYZE SELECT file_parent_dir, file_name, file_display
> > FROM file_info_7 WHERE file_type='d' ORDER BY file_parent_dir ASC,
> > file_name ASC;
>
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