Re: Index Skip Scan (new UniqueKeys)

On Mon, Jan 24, 2022 at 8:51 AM Dmitry Dolgov <9erthalion6(at)gmail(dot)com> wrote:

> > On Sun, Jan 23, 2022 at 04:25:04PM -0800, Zhihong Yu wrote:
> > On Sat, Jan 22, 2022 at 1:32 PM Dmitry Dolgov <9erthalion6(at)gmail(dot)com>
> wrote:
> > > Besides that the new patch version contains some cleaning up and
> > > addresses commentaries around leaf page pinning from [1]. The idea
> > > behind the series structure is still the same: the first three patches
> > > contains the essence of the implementation (hoping to help concentrate
> > > review), the rest are more "experimental".
> > >
> > > [1]:
> > >
> https://www.postgresql.org/message-id/flat/CAH2-WzmUscvoxVkokHxP=uPTDjSi0tJkFpUPD-CeA35dvn-CMw(at)mail(dot)gmail(dot)com
> >
> > Hi,
> >
> > + /* If same EC already is already in the list, then not unique */
> >
> > The word already is duplicated.
> >
> > + * make_pathkeys_for_uniquekeyclauses
> >
> > The func name in the comment is different from the actual func name.
>
> Thanks for the review! Right, both above make sense. I'll wait a bit if
> there will be more commentaries, and then post a new version with all
> changes at once.
>
> > + * Portions Copyright (c) 2020, PostgreSQL Global Development Group
> >
> > The year should be 2022 :-)
>
> Now you see how old is this patch :)
>
> > make_pathkeys_for_uniquekeys() is called by build_uniquekeys(). Should
> > make_pathkeys_for_uniquekeys() be moved into uniquekeys.c ?
>
> It's actually placed there by analogy with make_pathkeys_for_sortclauses
> (immediately preceding function), so I think moving it into uniquekeys
> will only make more confusion.
>
> > +query_has_uniquekeys_for(PlannerInfo *root, List *path_uniquekeys,
> > + bool allow_multinulls)
> >
> > It seems allow_multinulls is not checked in the func. Can the parameter
> be
> > removed ?
>
> Right, it could be removed. I believe it was somewhat important when the
> patch was tightly coupled with the UniqueKeys patch, where it was put in
> use.
>
> Hi,
It would be nice to take out this unused parameter for this patch.

The parameter should be added in patch series where it is used.

Cheers