On 17 November 2015 at 15:43, Jim Nasby <jim.na...@bluetreble.com> wrote: > On 11/17/15 4:41 AM, Thom Brown wrote: >> >> Could someone post a TL;DR summary of what the current plan looks >> like? I can see there is a huge amount of discussion to trawl back >> through. I can see it's something to do with the visibility map. And >> does it avoid freezing very large tables like the title originally >> sought? > > > Basically, it follows the same pattern that all-visible bits do, except > instead of indicating a page is all-visible, the bit shows that all tuples > on the page are frozen. That allows a scan_all vacuum to skip those pages.
So the visibility map is being repurposed? And if a row on a frozen page is modified, what happens to the visibility of all other rows on that page, as the bit will be set back to 0? I think I'm missing a critical part of this functionality. Thom -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
