Re: HOT chain validation in verify_heapam()

Hi,

On 2022-11-14 15:07:05 -0800, Peter Geoghegan wrote:
> I'd really like to know if the scary HOT chain freezing scenario is
> possible, for the very obvious reason. Have you tried to write a test
> case for that?

I tried. Unfortunately, even if the bug exists, we currently don't have the
infrastructure to write isolationtester tests for it. There's just too many
points where we'd need to wait where I don't know of ways to wait with
isolationtester.

I'm quite certain that it's possible to end up freezing an earlier row
versions in a hot chain in < 14, I got there with careful gdb
orchestration. Of course possible I screwed something up, given I did it once,
interactively. Not sure if trying to fix it is worth the risk of backpatching
all the necessary changes to switch to the retry approach.

Greetings,

Andres Freund