Re: reloption to prevent VACUUM from truncating empty pages at the end of relation

I wrote:
> Pavan Deolasee <pavan.deolasee@gmail.com> writes:
>> What if we remember the buffers as seen by count_nondeletable_pages() and
>> then just discard those specific buffers instead of scanning the entire
>> shared_buffers again?

> That's an idea.

BTW, before pushing too hard on any of this, we need to think about the
data-corruption hazard that MauMau just reminded us about.  I'm afraid
what we're likely to end up with after the dust settles is worse
performance than today, not better :-(.

https://postgr.es/m/5BBC590AE8DF4ED1A170E4D48F1B53AC@tunaPC

            regards, tom lane