Re: trying again to get incremental backup

On Mon, Nov 20, 2023 at 2:10 PM Robert Haas <robertmhaas@gmail.com> wrote:
> > Is this meant to support multiple timelines each with non-overlapping
> > adjacent ranges, rather than multiple non-adjacent ranges?
>
> Correct. I don't see how non-adjacent LSN ranges could ever be a
> useful thing, but adjacent ranges on different timelines are useful.

Thinking about this a bit more, there are a couple of things we could
do here in terms of syntax. Once idea is to give up on having a
separate MANIFEST-WAL-RANGE command for each range and instead just
cram everything into either a single command:

MANIFEST-WAL-RANGES {tli} {startlsn} {endlsn}...

Or even into a single option to the BASE_BACKUP command:

BASE_BACKUP yadda yadda INCREMENTAL 'tli@startlsn-endlsn,...'

Or, since we expect adjacent, non-overlapping ranges, you could even
arrange to elide the duplicated boundary LSNs, e.g.

MANIFEST_WAL-RANGES {{tli} {lsn}}... {final-lsn}

Or

BASE_BACKUP yadda yadda INCREMENTAL 'tli@lsn,...,final-lsn'

I'm not sure what's best here. Trying to trim out the duplicated
boundary LSNs feels a bit like rearrangement for the sake of
rearrangement, but maybe it isn't really.

--
Robert Haas
EDB: http://www.enterprisedb.com