Re: Re: rfd: multi-key GiST index problems

Oleg Bartunov <oleg@sai.msu.su>

From: Oleg Bartunov <oleg@sai.msu.su>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: <pgsql-bugs@postgresql.org>
Date: 2001-05-25T09:39:43Z
Lists: pgsql-bugs
On Wed, 23 May 2001, Tom Lane wrote:

>
> indexRelation->rd_am->amsupport, cf. InitIndexStrategy.

Thanks Tom

>
> >    In third example with multi-key index we
> >    forced to use 'with (islossy)' for all index even if select will
> >    use index by first attribute (b gist_box_ops) which is a not right
> >    thing.
>
> islossy is a per-index attribute, not a per-column attribute.  I don't
> think it makes sense to define it any other way.  If any one of the
> columns is stored in a lossy fashion, then the index is lossy.

Not always. If we have multi-key index and only 2nd column requires lossy
why do we need to check lossiness if select only 1st column ?
It's not a high priority, but some optimization would be fine.


>
> 			regards, tom lane
>
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	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
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