Re: Potential ABI breakage in upcoming minor releases

David E. Wheeler <david@justatheory.com>

From: "David E. Wheeler" <david@justatheory.com>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Noah Misch <noah@leadboat.com>, Aleksander Alekseev <aleksander@timescale.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Marco Slot <marco.slot@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Christoph Berg <myon@debian.org>, Pavan Deolasee <pavan.deolasee@gmail.com>

Date: 2024-11-16T16:04:40Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Undo unintentional ABI break in struct ResultRelInfo.
- ee33d58471de 16.6 landed
- 6bfacd368bb4 17.2 landed
- 17db248f318f 15.10 landed
- 099e711b77b8 14.15 landed
For inplace update durability, make heap_update() callers wait.
- 51ff46de29f6 16.5 cited
Fix btmarkpos/btrestrpos array key wraparound bug.
- 3fa81b62e09b 16.1 cited
Fix calculation of which GENERATED columns need to be updated.
- 8cd190e13a22 14.7 cited

On Nov 15, 2024, at 19:30, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> That text says exactly nothing about what specific code changes to
> make or not make.  I'm not sure offhand where (or if) we have this
> documented, but there's an idea that adding fields at the end of
> a struct is safer ABI-wise than putting them in the middle.  Which
> is true if you can't squeeze them into padding space.  Here, that
> could have been done and probably should have.
> 
> The other bit of documentation we probably need is some annotation in
> struct ResultRelInfo saying "do not change the sizeof() this struct
> in back branches, period”.

This sounds like complementary documentation for committers; totally agree the guidance should be written down somewhere.

D