Re: HASH index method not correctly handling NULL text

Send a "NOTICE: Use of Hash index is deprecated, please use btree instead"
any time someone makes a hash index?

--rob

----- Original Message -----
From: "Bruce Momjian" <pgman@candle.pha.pa.us>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Neil Conway" <nconway@klamath.dyndns.org>;
<pgsql-general@postgresql.org>; <david.madore@ens.fr>
Sent: Monday, February 04, 2002 12:00 AM
Subject: Re: HASH index method not correctly handling NULL text


> Tom Lane wrote:
> > Neil Conway <nconway@klamath.dyndns.org> writes:
> > >> The warning should be suppressed for hash indexes, since they don't
> > >> include nulls.  I believe this is fixed in 7.2.
> >
> > > Is there a reason why hash indexes don't include NULLs?
> >
> > Nobody's got around to fixing them to do so.  AFAICS it should be easy
> > enough to do; just assign a fixed hash code (zero, likely) for NULLs,
> > and adjust the comparison routines to be NULL-conscious.
> >
> > If you want to work on the hash index code, feel free.  My own vision
> > of things says that we should put our effort into the btree and GIST
> > index types, which really cover the scalar and multidimensional cases
> > pretty effectively.  If we had unlimited manpower then it'd be worth
> > working on hash and rtree too, but I'd be just as happy leaving them
> > to rot quietly.
>
> The big question is how should we document the fact that hash isn't
> recommended?  We get periodic questions about it and I don't think the
> FAQ is the place for it because it is something pretty fundamental we
> should document.
>
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 853-3000
>   +  If your life is a hard drive,     |  830 Blythe Avenue
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>