Re: pg_control_checkpoint(): add "data_checksum_version" (Pg19)?

> On 11 Aug 2026, at 16:38, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>
> On Tue, Aug 11, 2026 at 3:07 AM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
>> I originally opted against displaying the mapped name to keep
>> pg_control_checkpoint a way to extract the raw data, but thinking about it
>> might be more useful to show the mapped value since the mapping is private.
>
> I suggested making pg_controldata report the latest checkpoint's checksum state
> as text rather than as a version. But, I found that pg_controldata reports
> similar information "Data page checksum version", and pg_control_init()
> exposes data_page_checksum_version as an integer version.
>
> This makes me wonder whether we should drop my suggestion and keep the latest
> checkpoint's checksum field as a version as well, or instead move toward
> reporting textual checksum states consistently in all these places.
> Or is there another approach that would make more sense?

I'm leaning towards using an integer representation in v19, which is the safe
option, and rethink it for v20 when we can consider it without any rush. A
compromise could be do document the integer <=> state name mapping in the
checksums section in the docs.

--
Daniel Gustafsson