Horton

Re: Enable data checksums by default

Greg Burd <greg@burd.me>

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From: Greg Burd <greg@burd.me>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, Tomas Vondra <tomas@vondra.me>, Peter Eisentraut <peter@eisentraut.org>, Heikki Linnakangas <hlinnaka@iki.fi>, Nathan Bossart <nathandbossart@gmail.com>, Greg Sabino Mullane <htamfids@gmail.com>, Bruce Momjian <bruce@momjian.us>, Michael Paquier <michael@paquier.xyz>, Michael Banck <mbanck@gmx.net>, Jeff Davis <pgsql@j-davis.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2025-07-31T13:39:43Z
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. Avoid BufferGetLSNAtomic() calls during nbtree scans.

  2. doc PG 18 relnotes: Add incompatibility note about checksums now default

  3. Fix pg_upgrade's cross-version tests when old < 18

  4. initdb: Change default to using data checksums.

  5. Allow TAP tests to force checksums off when calling init()

  6. initdb: Add new option "--no-data-checksums"

  7. Tweak docs to reduce possible impact of data checksums


> On Jul 30, 2025, at 8:09 AM, Daniel Gustafsson <daniel@yesql.se> wrote:
> 
>> On 30 Jul 2025, at 11:58, Laurenz Albe <laurenz.albe@cybertec.at> wrote:
>> 
>> On Tue, 2025-07-29 at 20:24 +0200, Tomas Vondra wrote:
>>> So, what should we do with the PG18 open item? We (the RMT team) would
>>> like to know if we shall keep the checksums enabled by default, and if
>>> there's something that still needs to be done for PG18.
>> 
>> I don't have a strong opinion, but I lean towards having them on
>> by default.
> 
> I agree with that, while there might be a lot of cases where disabling
> checksums is the right move it's still a sane default.
> 
> --
> Daniel Gustafsson

I realize I’m late to the conversation, I’ve been lurking...

I agree that enabling checksums by default is the sane default.  Databases
should always make a best effort for data integrity, checksums are a
positive step in that direction.

I recall a conversation at the last PGConf.dev (2025) with a representative
from Intel and Jeff Davis (CC’ed) that had to do with checksums and a vast
performance difference between Intel and AMD the latter winning by a mile.
I forget the details, maybe Jeff remembers more than I do.  I’m not
suggesting that we disable Intel by default or trying to derail this
conversation (which appears to be reaching consensus), just raising
awareness.

best,

-greg