RE: [PATCH] Use indexes on the subscriber when REPLICA IDENTITY is full on the publisher - Mailing list pgsql-hackers

On Fri, Mar 10, 2023 8:17 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> 
> On Fri, Mar 10, 2023 at 5:16 PM Önder Kalacı <onderkalaci@gmail.com> wrote:
> >
> >>
> >> wip_for_optimize_index_column_match
> >> +static bool
> >> +IndexContainsAnyRemoteColumn(IndexInfo  *indexInfo,
> >> + LogicalRepRelation  *remoterel)
> >> +{
> >> + for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
> >> + {
> >>
> >> Wouldn't it be better to just check if the first column is not part of
> >> the remote column then we can skip that index?
> >
> >
> > Reading [1], I think I can follow what you suggest. So, basically,
> > if the leftmost column is not filtered, we have the following:
> >
> >>  but the entire index would have to be scanned, so in most cases the planner
> would prefer a sequential table scan over using the index.
> >
> >
> > So, in our case, we could follow a similar approach. If the leftmost column of
> the index
> > is not sent over the wire from the pub, we can prefer the sequential scan.
> >
> > Is my understanding of your suggestion accurate?
> >
> 
> Yes. I request an opinion from Shi-San who has reported the problem.
> 

I also agree with this.
And I think we can mention this in the comments if we do so.

Regards,
Shi Yu