Horton

Re: Consistently use the XLogRecPtrIsInvalid() macro

Álvaro Herrera <alvherre@kurilemu.de>

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From: Álvaro Herrera <alvherre@kurilemu.de>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Peter Eisentraut <peter@eisentraut.org>, Michael Paquier <michael@paquier.xyz>, Heikki Linnakangas <hlinnaka@iki.fi>, Quan Zongliang <quanzongliang@yeah.net>, pgsql-hackers@lists.postgresql.org
Date: 2025-11-06T19:48:11Z
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 →

  1. Replace literal 0 with InvalidXLogRecPtr for XLogRecPtr assignments

  2. Replace pointer comparisons and assignments to literal zero with NULL

  3. Use XLogRecPtrIsValid() in various places

  4. Introduce XLogRecPtrIsValid()

On 2025-Nov-06, Bertrand Drouvot wrote:

> I see, I would have introduced XLogRecPtrIsInvalid() on the back branches only
> if there is a need to (a bugfix that would make use of it). But yeah, I agree
> that would add extra "unnecessary" work, so done as you suggested in the
> attached. I checked that 0001 apply on the [14-18]_STABLE branches successfully.

Okay, thanks, I have applied that one to all stable branches, except I
didn't add the judgemental comment about XLogRecPtrIsInvalid().

I also pushed 0002+0004+0005 together as one commit, so now we have
XLogRecPtrIsValid() everywhere.

I did a couple of minor transformations, where the new code would end
doing "!XLogRecPtrIsValid(x) ? A : B" it seems clearer to remove the
negation and invert the other two arguments in the ternary.  We also had
this assertion,

-   Assert(XLogRecPtrIsInvalid(state->istartpoint) == (state->istarttli == 0));

which was being transformed to have a negation.  I chose to negate the
other side of the equality instead, that is,

+   Assert(XLogRecPtrIsValid(state->istartpoint) == (state->istarttli != 0));

which also seems clearer.

Now only 0003 remains ... I would change the complaining version to 21
there, because why not?

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
Maybe there's lots of data loss but the records of data loss are also lost.
(Lincoln Yeoh)