Horton

Re: Direct I/O

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Andrew Dunstan <andrew@dunslane.net>, Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, Christoph Berg <myon@debian.org>, mikael.kjellstrom@gmail.com, pgsql-hackers@postgresql.org
Date: 2023-05-14T21:09:19Z
Lists: pgsql-hackers 
On Mon, May 01, 2023 at 02:47:57PM +1200, Thomas Munro wrote:
> On Mon, May 1, 2023 at 12:00 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Justin Pryzby <pryzby@telsasoft.com> writes:
> > > Since this is -currently- a developer-only feature, it seems reasonable
> > > to rename the GUC to debug_direct_io, and (at such time as it's
> > > considered to be helpful to users) later rename it to direct_io.
> >
> > +1
> 
> Yeah, the future cross-version confusion thing is compelling.  OK,
> here's a rename patch.

This looks reasonable.

Commits

  1. Rename hook functions for debug_io_direct to match variable name.

  2. Rename io_direct to debug_io_direct.

  3. Skip the 004_io_direct.pl test if a pre-flight check fails.

  4. Use higher wal_level for 004_io_direct.pl.

  5. Skip \password TAP test on old IPC::Run versions

  6. Add io_direct setting (developer-only).

  7. Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.

  8. Add palloc_aligned() to allow aligned memory allocations

  9. initdb: When running CREATE DATABASE, use STRATEGY = WAL_COPY.