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Subject: Re: pgsql: Online enabling and disabling of data checksums
From: Daniel Gustafsson <dgustafsson@postgresql.org>
In-Reply-To: 
 <CAJ7c6TPRTnQFXXX1CRcYoTLXw2swtDH==uSz1MYoMKdLrKZHjA@mail.gmail.com>
Date: Mon, 6 Apr 2026 16:57:43 +0200
Cc: pgsql-committers@lists.postgresql.org
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 <CAJ7c6TPRTnQFXXX1CRcYoTLXw2swtDH==uSz1MYoMKdLrKZHjA@mail.gmail.com>
To: Aleksander Alekseev <aleksander@tigerdata.com>
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> On 6 Apr 2026, at 16:39, Aleksander Alekseev =
<aleksander@tigerdata.com> wrote:
>=20
> Hi Daniel,
>=20
>> Online enabling and disabling of data checksums
>>=20
>> [...]
>=20
> I noticed a little mistake:

Thanks for looking!

> ```
> /*
> * Await state transition to "on" in all backends. When done we know =
that
> * data data checksums are both written and verified in all backends.
> */
> ```
>=20
> The word "data" is repeated twice.

Ugh.

> Also there are inconsistencies in the way
> XLogCtlData->data_checksum_version,
> ControlFileData->data_checksum_version and certain variables are
> assigned. Sometimes a hardcoded 0 is used and sometimes
> PG_DATA_CHECKSUM_OFF. I suggest using values of the enum
> ChecksumStateType for readability / consistency.

PG_DATA_CHECKSUM_OFF didn't exist until quite late in the lifetime of =
the
patch, and clearly not all uses of 0 were ported over.

> Here are corresponding patches.

I will take another look later today when I have more time, and commit =
them.

--
Daniel Gustafsson