Re: [PoC] pg_upgrade: allow to upgrade publisher node

On Tue, Oct 3, 2023 at 9:58 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> On Fri, Sep 29, 2023 at 5:27 PM Hayato Kuroda (Fujitsu)
> <kuroda(dot)hayato(at)fujitsu(dot)com> wrote:
> >
> > Yeah, the approach enforces developers to check the decodability.
> > But the benefit seems smaller than required efforts for it because the function
> > would be used only by pg_upgrade. Could you tell me if you have another use case
> > in mind? We may able to adopt if we have...
>
> I'm attaching 0002 patch (on top of v45) which implements the new
> decodable callback approach that I have in mind. IMO, this new
> approach is extensible, better than the current approach (hard-coding
> of certain WAL records that may be generated during pg_upgrade) taken
> by the patch, and helps deal with the issue that custom WAL resource
> managers can have with the current approach taken by the patch.

I did not see the patch, but I like this approach better. I mean this
approach does not check what record types are generated during updagre
instead this directly targets that after the confirmed_flush_lsn what
type of records shouldn't be generated. So if rmgr says that after
commit_flush_lsn no decodable record was generated then we are safe to
upgrade that slot. So this seems an expandable approach.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com