Horton

Re: Relation bulk write facility

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Peter Smith <smithpb2250@gmail.com>, Robert Haas <robertmhaas@gmail.com>, vignesh C <vignesh21@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2024-02-24T20:26:12Z
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. Relax fsyncing at end of a bulk load that was not WAL-logged

  2. Fix cross-version upgrade tests after f0827b443.

  3. Remove AIX support

  4. Fix compiler warning on typedef redeclaration

  5. Introduce a new smgr bulk loading facility.

On Sun, Feb 25, 2024 at 09:13:47AM +1300, Thomas Munro wrote:
> On Sun, Feb 25, 2024 at 9:12 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> > On Sun, Feb 25, 2024 at 8:50 AM Noah Misch <noah@leadboat.com> wrote:
> > > On GNU/Linux x64, gcc correctly records alignment=2**12 for the associated
> > > section (.rodata for bulk_write.o zero_buffer, .bss for pg_prewarm.o
> > > blockbuffer).  If I'm reading this right, neither AIX gcc nor xlc is marking
> > > the section with sufficient alignment, in bulk_write.o or pg_prewarm.o:
> >
> > Ah, that is a bit of a hazard that we should probably document.
> >
> > I guess the ideas to fix this would be: use smgrzeroextend() instead
> > of this coding, and/or perhaps look at the coding of pg_pwrite_zeros()
> > (function-local static) for any other place that needs such a thing,
> > if it would be satisfied by function-local scope?

True.  Alternatively, could arrange for "#define PG_O_DIRECT 0" on AIX, which
disables the alignment assertions (and debug_io_direct).

> Erm, wait, how does that function-local static object work differently?

I don't know specifically, but I expect they're different parts of the gcc
implementation.  Aligning an xcoff section may entail some xcoff-specific gcc
component.  Aligning a function-local object just changes the early
instructions of the function; it's independent of the object format.