Re: Fix possible 'unexpected data beyond EOF' on replica restart

On 12/01/2026 10:34, Anthonin Bonnefoy wrote:
> Here's a new version with a bit of rewording.

Applied to all branches. Thanks!

I left out this comment change on smgrtruncate():

> @@ -870,6 +870,9 @@ smgrnblocks_cached(SMgrRelation reln, ForkNumber forknum)
> * be called in a critical section, but the current size must be checked
> * outside the critical section, and no interrupts or smgr functions relating
> * to this relation should be called in between.
> + *
> + * If the specified number of blocks is higher than the current size, the
> + * request is ignored when we are InRecovery, otherwise, an error is raised.
> */
> void
> smgrtruncate(SMgrRelation reln, ForkNumber *forknum, int nforks,

I would love to have a comment along those lines, but I think it's
misleading here, because smgrtruncate() actually does a few things even
when the requested size is greater than the current size: it
nevertheless calls DropRelationBuffers(), CacheInvalidateSmgr(), and
updates the cached sizes in the SmgrRelation. So it seems misleading to
say the request is ignored.

I wasn't sure how to phrase that, so I just left out that comment
change. I'm open to proposals on a good wording though.

(The similar comment in mdnblocks() is accurate, mdnblocks() bails out
very early, so I kept that)

- Heikki