Re: HOT patch - version 15

"Pavan Deolasee" <pavan.deolasee@gmail.com> writes:
> Pruning removes intermediate dead tuples by marking their line pointers
> ~LP_USED and redirecting the root line pointer to the first
> live/recently_dead tuple in the chain.

It seems utterly unsafe to do this without a vacuum-grade lock on the
page.  Someone might be examining the root tuple (eg, in a SnapshotAny
scan) and I think they are entitled to assume that the line pointer
stays valid while they are looking at the tuple.

            regards, tom lane