Re: ltree and ordering - what index?

From: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
To: hubert depesz lubaczewski <depesz(at)gmail(dot)com>
Cc: PostgreSQL General <pgsql-general(at)postgresql(dot)org>
Subject: Re: ltree and ordering - what index?
Date: 2005-09-20 22:49:34
Message-ID: 20050920224934.GA7630@pervasive.com
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On Mon, Sep 19, 2005 at 07:23:54AM +0200, hubert depesz lubaczewski wrote:
> On 9/18/05, Jim C. Nasby <jnasby(at)pervasive(dot)com> wrote:
> >
> > ltree is part of contrib, right?
>
>
>
> yes.
>
> You probably need to define a functional index of some kind. How are you
> > querying now? IIRC you'll be doing something like region IN (ltree)?
> >
>
> i didn't thought about functional indices, but this might be a solution.
> have to think about it for a while
> searching through ltree's is done using specific operators (>@).

Yes, which is something I don't think the indexing code can deal with.

IIRC you're looking for a way to index something that's in a specific
place in the ltree, so you'd want to index that actual function
expression.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461

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