Re: WIP: Covering + unique indexes.

On Tue, Apr 3, 2018 at 7:02 AM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:

> On Mon, Apr 2, 2018 at 4:27 PM, Alexander Korotkov
> <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> > I thought abut that another time and I decided that it would be safer
> > to use 13th bit in index tuple flags. There are already attempt to
> > use whole 6 bytes of tid for not heap pointer information [1]. Thus, it
> > would be safe to use 13th bit for indicating alternative offset meaning
> > in pivot tuples, because it wouldn't block further work. Revised
> patchset
> > in the attachment implements it.
>
> This is definitely not the only time someone has talked about this
> 13th bit -- it's quite coveted. It also came up with UPSERT, and with
> WARM. That's just the cases that I can personally remember.
>
> I'm glad that you found a way to make this work, that will keep things
> flexible for future patches, and make testing easier. I think that we
> can find a flexible representation that makes almost everyone happy.
>

OK, good.

I didn't have time to look at this properly today, but I will try to
> do so tomorrow.
>

Great, I'm looking forward your feedback.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company