| From: | Craig James <cjames(at)emolecules(dot)com> |
|---|---|
| To: | Janek Sendrowski <janek12(at)web(dot)de> |
| Cc: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: ORDER BY using index, tsearch2 |
| Date: | 2013-12-11 23:38:09 |
| Message-ID: | CAFwQ8rc=R=S3RFZzQkGjNgYpQQHQcyA9NAw+aU45SK-mniKPMg@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On Wed, Dec 11, 2013 at 2:29 PM, Janek Sendrowski <janek12(at)web(dot)de> wrote:
> Hi,
>
> How can I use this ORDER BY using index feature presented in this
> implementation.
> It doesn't seem to be in use, when I have a look in my query plan.
> It still does an cost intensive Bitmap Heap Scan and a Bitmap Index scan.
> I also can't find the "><" operator in any introduction of the tsearch2
> extension.
> Is it just an idea?
>
A GIST is a tree, but there's no notion of ">" or "<", only yes/no at each
tree branch. In this regard a GIST index is more like a hash table. You
can't use a hash table to sort. It doesn't make sense.
Craig
> Thanks for your help!
> Janek Sendrowski
>
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2013-12-11 23:55:57 | Re: ORDER BY using index, tsearch2 |
| Previous Message | Tom Lane | 2013-12-11 23:33:32 | Re: ORDER BY using index, tsearch2 [READ THIS!] |