Re: backup manifests

On Tue, Mar 31, 2020 at 11:10 AM Noah Misch <noah(at)leadboat(dot)com> wrote:
>
> On Mon, Mar 30, 2020 at 12:16:31PM -0700, Andres Freund wrote:
> > On 2020-03-30 15:04:55 -0400, Robert Haas wrote:
> > > I guess I'd like to be clear here that I have no fundamental
> > > disagreement with taking this tool in any direction that people would
> > > like it to go. For me it's just a question of timing. Feature freeze
> > > is now a week or so away, and nothing complicated is going to get done
> > > in that time. If we can all agree on something simple based on
> > > Andres's recent proposal, cool, but I'm not yet sure that will be the
> > > case, so what's plan B? We could decide that what I have here is just
> > > too little to be a viable facility on its own, but I think Stephen is
> > > the only one taking that position. We could release it as
> > > pg_validatemanifest with a plan to rename it if other backup-related
> > > checks are added later. We could release it as pg_validatebackup with
> > > the idea to avoid having to rename it when more backup-related checks
> > > are added later, but with a greater possibility of confusion in the
> > > meantime and no hard guarantee that anyone will actually develop such
> > > checks. We could put it in to pg_checksums, but I think that's really
> > > backing ourselves into a corner: if backup validation develops other
> > > checks that are not checksum-related, what then? I'd much rather
> > > gamble on keeping things together by topic (backup) than technology
> > > used internally (checksum). Putting it into pg_basebackup is another
> > > option, and would avoid that problem, but it's not my preferred
> > > option, because as I noted before, I think the command-line options
> > > will get confusing.
> >
> > I'm mildly inclined to name it pg_validate, pg_validate_dbdir or
> > such. And eventually (definitely not this release) subsume pg_checksums
> > in it. That way we can add other checkers too.
>
> Works for me; of those two, I prefer pg_validate.
>

pg_validate sounds like a tool with a much bigger purpose. I think
even things like amcheck could also fall under it.

This patch has two parts (a) Generate backup manifests for base
backups, and (b) Validate backup (manifest). It seems to me that
there are not many things pending for (a), can't we commit that first
or is it the case that (a) depends on (b)? This is *not* a suggestion
to leave pg_validatebackup from this release rather just to commit if
something is ready and meaningful on its own.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com