Re: Consistently use the XLogRecPtrIsInvalid() macro

Michael Paquier <michael@paquier.xyz>

From: Michael Paquier <michael@paquier.xyz>

To: Heikki Linnakangas <hlinnaka@iki.fi>

Cc: Quan Zongliang <quanzongliang@yeah.net>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, pgsql-hackers@lists.postgresql.org

Date: 2025-10-28T13:10:08Z

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 →

Replace literal 0 with InvalidXLogRecPtr for XLogRecPtr assignments
- ec3174407164 19 (unreleased) landed
Replace pointer comparisons and assignments to literal zero with NULL
- ec782f56b0c3 19 (unreleased) landed
Use XLogRecPtrIsValid() in various places
- a2b02293bc65 19 (unreleased) landed
Introduce XLogRecPtrIsValid()
- d2965f627fe3 14.20 landed
- c0031d461324 18.1 landed
- 723cc84db50a 16.11 landed
- 49b45999f3b2 15.15 landed
- 33727aff18d0 17.7 landed
- 20bafb097288 13.23 landed
- 06edbed47862 19 (unreleased) landed

On Tue, Oct 28, 2025 at 01:40:24PM +0200, Heikki Linnakangas wrote:
> It's also a bit cumbersome that we have XLogRecPtrIsInvalid() rather than
> XLogRecPtrIsValid(). That's inconsistent with OidIsValid and
> TransactionIdInValid, and it leads to an awkward double negative 'if
> (!XLogRecPtrIsInvalid(x))' if you want to check that 'x' is valid.
> 
> Overall I'm inclined to do nothing. But if anything, perhaps introduce
> XLogRecPtrIsValid(x) and switch to that, or replace XLogRecPtrIsInvalid(x)
> calls with 'x == InvalidXLogRecPtr'

The annoying part with eliminating XLogRecPtrIsInvalid() or replacing
it is that a bunch of external code would be broken, particularly
backup tools.  I'd rather leave the beast alone.
--
Michael