Horton

Re: Direct I/O

Andrea Gelmini <andrea.gelmini@gmail.com>

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From: Andrea Gelmini <andrea.gelmini@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andrew Dunstan <andrew@dunslane.net>, Heikki Linnakangas <hlinnaka@iki.fi>, Noah Misch <noah@leadboat.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@postgresql.org
Date: 2023-04-10T07:04:22Z
Lists: pgsql-hackers 
Il giorno lun 10 apr 2023 alle ore 04:58 Andres Freund
<andres@anarazel.de> ha scritto:
> We should definitely let the brtfs folks know of this issue... It's possible
> that this bug was recently introduced even. What kernel version did you repro
> this on Thomas?

In these days on BTRFS ml they are discussing about Direct I/O data
corruption. No patch at the moment, they are still discussing how to
address it:
https://lore.kernel.org/linux-btrfs/aa1fb69e-b613-47aa-a99e-a0a2c9ed273f@app.fastmail.com/

Ciao,
Gelma

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.