Re: basebackup: do not verify checksums on pages written before enabling checksums

> On 17 Aug 2026, at 10:36, Yilin Zhang <jiezhilove(at)126(dot)com> wrote:

> For regression‑test scenarios simulating the "exactly‑one‑page‑failure‑per‑file" fault, there is a blind spot in the counter.
> The final ERROR on total_checksum_failures in basebackup.c will still abort the backup, but this check can become ineffective.

I might be missing what you are referring to, isn't the check for the backup
command not failing catching this?

> In this scenario, if a user starts a backup a few seconds before enable completes, the entire backup skips all page checksums.
> Users will obtain a backup with zero checksum validation, while believing checksum verification is enabled.

There is little we can do though isn't there? If a backup completes seconds
before inserting very important data then that data isn't backed up, we cannot
foresee what the user might do and we cannot foresee a checksum enabling
finishing in time so we should wait. The effects on verification during a
backup should however be documented.

--
Daniel Gustafsson