Re: Horribly slow hash join

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Dennis Bjorklund <db(at)zigo(dot)dhs(dot)org>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Jim C(dot) Nasby" <jim(at)nasby(dot)net>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Horribly slow hash join
Date: 2004-04-19 03:15:54
Message-ID: 20040419031554.GA1881@wolff.to
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On Sun, Apr 18, 2004 at 18:27:09 +0200,
Dennis Bjorklund <db(at)zigo(dot)dhs(dot)org> wrote:
> On Sun, 18 Apr 2004, Tom Lane wrote:
>
> > > What do you mean? int8 is supported on all platformas
> >
> > No it isn't.
>
> So on platforms where it isn't you would use int4 as the biggest int then.
> I don't really see that as a problem. As long as you calculate the hash on
> the biggest int on that platform it should work.

Another option would be to put the numbers into two int4s. For int4 or
smaller types one of these would be zero. int8s would be split between
the two. The hash function would then be defined on the two int4s.

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