Re: Remove remnants of "snapshot too old"

Hi,

On 2024-12-03 22:06:59 +0200, Heikki Linnakangas wrote:
> I spotted some more remnants of the "snapshot too old" feature that was
> removed in v17. Barring objections, I will commit the attached patch to tidy
> up.

Most of this I agree with. But I'm not sure just removing the toast snapshot
stuff is good - we've had a bunch of bugs where we don't hold a snapshot for
long enough to actually ensure that toast tuples stay alive. It's not legal to
fetch a toast id in one snapshot, release that, and then fetch the toast tuple
with a fresh snapshot. I think the removal of

> - if (snapshot == NULL)
> - elog(ERROR, "cannot fetch toast data without an active snapshot");

will make it easier to introduce further such bugs?

Greetings,

Andres Freund