On Tue, Mar 7, 2017 at 9:12 PM, Andres Freund <andres@anarazel.de> wrote:
> > I wonder however, if careful snapshot managment couldn't solve this as > well. I have *not* thought a lot about this, but afaics we can easily > prevent all-visible from being set in cases it'd bother us by having an > "appropriate" xmin / registered snapshot.
Yeah, but that's a tax on the whole system.
May be we can do that only when patched CIC (or any other operation which may not like concurrent VM set) is in progress. We could use what Stephen suggested upthread to find that state. But right now it's hard to think because there is nothing on either side so we don't know what gets impacted by aggressive VM set and how.