On Mon, Dec 19, 2022 at 6:41 AM Maxim Orlov <orlovmg@gmail.com> wrote:
>
> As always, reviews and opinions are very welcome.
Hi! I think that 64-bit xids are a very important feature and I want
to help advance it. That's why I want to try to understand a patch
better.
Do I get it right that the proposed v51 patchset only changes the SLRU
filenames and type of pageno representation? Is SLRU wraparound still
exactly there after 0xFFFFFFFF byte?
The thing is we had some nasty bugs because SLRU wraparound is tricky.
And I think it would be beneficial if we could get to continuous SLRU
space. But the patch seems to avoid addressing this problem.
Also, I do not understand what is the reason for splitting 1st and 2nd
steps. Certainly, there must be some logic behind it, but I just can't
grasp it...
And the purpose of the 3rd step with pg_upgrade changes is a complete
mystery for me. Please excuse my incompetence in the topic, but maybe
some commit message or comments would help. What kind of xact segments
conversion we do? Why is it only necessary for xacts, but not other
SLRUs?
Thank you for working on this important project!
Best regards, Andrey Borodin.