Re: Conflict Detection and Resolution - Mailing list pgsql-hackers

From Peter Smith
Subject Re: Conflict Detection and Resolution
Date
Msg-id CAHut+PtohfVFXKM10eWLw8PwVQrX=U_kjgG-JLsok8PwCB9zsw@mail.gmail.com
Whole thread Raw
In response to Re: Conflict Detection and Resolution  (shveta malik <shveta.malik@gmail.com>)
Responses Re: Conflict Detection and Resolution
List pgsql-hackers
On Mon, Sep 30, 2024 at 4:29 PM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Mon, Sep 30, 2024 at 11:04 AM Peter Smith <smithpb2250@gmail.com> wrote:
> >
> > On Mon, Sep 30, 2024 at 2:27 PM shveta malik <shveta.malik@gmail.com> wrote:
> > >
> > > On Fri, Sep 27, 2024 at 1:00 PM Peter Smith <smithpb2250@gmail.com> wrote:
> > >
> > > > ~~~
> > > >
> > > > 14.
> > > > 99. General - ordering of conflict_resolver
> > > >
> > > > nit - ditto. Let's name these in alphabetical order. IMO it makes more
> > > > sense than the current random ordering.
> > > >
> > >
> > >  I feel ordering of resolvers should be same as that of conflict
> > > types, i.e. resolvers of insert variants first, then update variants,
> > > then delete variants. But would like to know what others think on
> > > this.
> > >
> >
> > Resolvers in v14 were documented in this random order:
> > error
> > skip
> > apply_remote
> > keep_local
> > apply_or_skip
> > apply_or_error
> >
>
> Yes, these should be changed.
>
> > Some of these are resolvers for different conflicts. How can you order
> > these as "resolvers for insert" followed by "resolvers for update"
> > followed by "resolvers for delete" without it all still appearing in
> > random order?
>
> I was thinking of ordering them like this:
>
> apply_remote:              applicable to insert_exists, update_exists,
> update_origin_differ, delete_origin_differ
> keep_local:                   applicable to insert_exists,
> update_exists,  update_origin_differ, delete_origin_differ
> apply_or_skip:              applicable to update_missing
> apply_or_error :            applicable to update_missing
> skip:                              applicable to update_missing and
> delete_missing
> error:                             applicable to all.
>
> i.e. in order of how they are applicable to conflict_types starting
> from insert_exists till delete_origin_differ  (i.e. reading
> ConflictTypeResolverMap, from left to right and then top to bottom).
> Except I have kept 'error' at the end instead of keeping it after
> 'keep_local' as the former makes more sense there.
>

This proves my point because, without your complicated explanation to
accompany it, the final order (below) just looks random to me:
apply_remote
keep_local
apply_or_skip
apply_or_error
skip
error

Unless there is some compelling reason to do it differently, I still
prefer A-Z (the KISS principle).

======
Kind Regards,
Peter Smith.
Fujitsu Australia



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