Horton

Re: Direct I/O

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Noah Misch <noah@leadboat.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: 2023-05-01T00:00:01Z
Lists: pgsql-hackers 
Justin Pryzby <pryzby@telsasoft.com> writes:
> On Sun, Apr 30, 2023 at 06:35:30PM +1200, Thomas Munro wrote:
>> What about a
>> warning message about that at startup if it's on?

> Such a warning wouldn't be particularly likely to be seen by someone who
> already didn't read/understand the docs for the not-feature that they
> turned on.

Yeah, I doubt that that would be helpful at all.

> 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

			regards, tom lane

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.