Re: XLog size reductions: Reduced XLog record header size for PG17

On Mon, 3 Jul 2023 at 13:08, Matthias van de Meent
<boekewurm+postgres@gmail.com> wrote:
>
> On Fri, 30 Jun 2023 at 17:36, Matthias van de Meent
> <boekewurm+postgres@gmail.com> wrote:
> >
> > Hi,
> >
> > The attached v2 patchset contains some small fixes for the failing
> > cfbot 32-bit tests - at least locally it does so.
> >
> > I'd overlooked one remaining use of MAXALIGN64() in xlog.c in the last
> > patch of the set, which has now been updated to XLP_ALIGN as well.
> > Additionally, XLP_ALIGN has been updated to use TYPEALIGN64 instead of
> > TYPEALIGN so that we don't lose bits of the aligned value in 32-bit
> > systems.
>
> Apparently there was some usage of MAXALIGN() in xlogreader that I'd
> missed, and which only shows up in TAP tests. In v3 I've fixed that,
> together with some improved early detection of invalid record headers.

Another fix for CFBot - pg_waldump tests which were added in 96063e28
exposed an issue in my patchset related to RM_INVALID_ID.

v4 splits former patch 0006 into two: now 0006 adds RM_INVALID and
does the rmgr-related changes in the code, and 0007 does the WAL disk
format overhaul.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech/)